Both things, to a certain extent, are true. A great deal of moddingdom does, it must be said, transcend traditional ideas of taste and decency in favor of looking like the sort of garish monstrosity you'd find parked in Dublin on a Saturday night. What you have to bear in mind is that, just because such case mods tend to get shown off the most, they're not the be all and end all of the form. There's a silent army of stylish, subtle mods out there, tailored to match the living room decor or sit sleekly next to an AV system. Case modding doesn't have hard and fast rules - it's about tailoring your PC to look the way you want it to. If that so happens to involve it appearing as though you've just ram-raided Autostyle, so be it.
To address the other stereotype, it's also true that making a really epic case mod requires a fearsome degree of time, patience and experience. However, a total overhaul may not necessarily be what you're after. A great many case mods involve just changing one or two specific things: for instance improving airflow, adding a side window or etching a pattern onto the side. A softly-softly approach has very little for a total newbie to fear.
The exact origins of case modding are lost to history - you could argue people applying Duran Duran stickers to their Spectrums or spray-painting their Armigas counts towards it - but there are certain flashpoints, defining moments that led to its creation. Modding's about two things: aesthetics and performance. In the case of the former, it grew out of the late 1990's sharp growth in overclocking that resulted from the PC's growing clout as a gaming platform.
People seeking more power out of their processors and graphics cards meant the components generated more heat, and in turn there was a need for extra cooling. Case mods for this purpose leant towards the functional, not the beautiful - mounts for fans, extra vents, fan speed controllers... De rigueur these days, but even a fitting for a single extra fan was crazy-talk for a mass-produced PC case back in 1997 or so. They may not have been pretty (they were often noisy to boot) but they led to the realization that a PC case was not an immutable object. It was a blank canvas, on which any design could be painted.
In vague tandem to this was the increasing mocking the traditional, dreary beige box case was being subjected to, culminating in the release of Apple's lurid but attention-grabbing iMac. All that translucent, candy-colored plastic is slightly risible by today's understated, mono-hued standards, but in 1998 it was like the first kid in school to get their ears pierced. Everyone wanted to copy it - and case modders moved faster than production lines did. There was this sudden awareness that the home computer could be a visual centerpiece to a room, not a dirty secret shoved underneath a table. Key to this was that the iMac's innards were partially on show, which bolstered the concept of celebrating PCs circuitry - most especially in the case of performance hardware. In other words, windows.
In many ways, a transparent side panel is the de facto case mod, to the point that a vast number of retail cases include one already. Irrespective, it remains one of the more satisfying and straightforward case mods for a first-timer. Pre-cut glass or acrylic windows are available from online case modding stores, so it's mostly a matter of sizing up and then cutting a dirty great hole in your case's side panel. Not quite as simple as it sounds, granted, but it's great for that 'I made this' feeling, and it's a form of modding that doesn't immediately make your PC look like it's from Glassgow. Beyond that are a thousand visual modifications of color and form. It's no coincidence that the rise of modding went hand-in-hand with the rise of home internet - budding modders were able to share their creations with similarly minded folks, offering and seeking inspiration and advice at sites like hardocp and virtual-hideout.
What began as individual experimentation grew into a huge community that in turn birthed standardization of parts and techniques - and plenty of good-natured competition. In due course, online stores sprang up to service this community, and as a result the bread and butter components of modding - tubing, lighting fans, front-mounted ports and displays, and even down to colored molex plugs and thumbscrews - are now easily and cheaply available. Contrast that with a decade ago, when fitting a fan or a light involved soldering and rewiring to connect it to your PC's power supply. Now such trinkets come with plug-and-play Molexs built-in, making installation a no-brainer.
Similarly, case fans are now standardized shapes and sizes, matching up neatly with the mounting points inside most PC cases, while most light fittings now come with Velcro or sticky back plastic for instant application. Between that and the sheer ubiquity of carved and sliced PC shells, we're now at the point where imagination is the major inhibiting factor to a great case mod.
Which leads us neatly to a third contributing factor to the scene - fanboyism. If you want to stand out from the crowd, any amount of neon strip lighting isn't going to get you noticed anymore, but a one-of-a-kind tribute to your favorite game or movie really will. The internet makes being a colossal Star Wars or Half-Life geek entirely acceptable, which is why we've seen PCs built inside R2D25, scale models of Futuromo's Bender and designed to look like Citadel 17. Clearly, this kind of stuff is a step beyond, involving a degree of craftsmanship as well as familiarity with the tools, plus isn't always ideal for the practicalities of running and upgrading a gaming PC. Something like a themed paint job or a carefully-etched logo is an achievable compromise.
Mod to Trot
Let's rewind a little to look at the nuts n bolts basics of modding. Say, for instance, your system is regularly overheating, you're out of fan mount points and water cooling sounds like the devil's work - what do you do? Clearly, you need to either blow additional cold air into the case or suck warm air out of it. Either way, you need an extra fan. In the simplest terms, fitting this involves measuring the diameter of the fan blades and cutting a hole to suit (just don't cut the hole to suit the square frame of the fan, or you won't have left any area to attach the thing to.) There are various ways to make the cut - a jigsaw, a rotary saw or a holesaw. The latter's the most preferable in this instance - it's a drillbit that cuts out a perfect circle, so there's minimal risk of ending up with a hole that looks like an egg drawn by Picasso after he'd had one too many triple-espressos. Presuming you're wanting to install a standard 80mm fan, you'll need a holesaw blade that's 76mm across -clearly, larger fans need larger holesaws.
You'll also need a work bench, a few clamps and a chunky bit of wood you don't need for anything else that you can pop underneath the casing as you cut into it. This is messy, fiddly business, and you don't want to end up with a coffee table covered in circular scars, or a severed finger. The backing board also prevents the case from bending and distorting as you inflict the wrath of mod upon it. None of this is expensive kit, but its well worth having a decent, semi-permanent setup in your garage or workshop, if case modding's something you intend to embark on regularly. Press the holesaw down firmly and gradually - it doesn't need to be spinning especially fast, and you should rest for a few seconds if it starts to feel crazy-hot.
Once you're done, the first thing you'll notice is that the wound isn't a clean one. The new hole will be inescapably raggedy-edged and running a finger along it will make your skin cry salty red tears, so don't do that. This is where, arguably the most archetypal case modding tool comes into play - the hallowed Dremel (or equivalent rotary tool - Dremel's simply the best-known brand). A Dremel's a small, low power electric drill, though rather than carving enormous holes, it's more designed for polishing and sanding and etching by means of small, precise fittings. To smooth out your circle, you want the sanding drum bit - move it gradually around the edge from the unpainted (i.e. inside) side of the case. This'll get rid of all those deadly sticky-bits, but you'll need to manually sand or take some steel wool to the cut to make it perfectly smooth.
Now you've made your hole, you've two options when it comes to actually fitting the fan, and they neatly sum up the essential dichotomy around case modding - aesthetics or practicality. In the case of the latter, you can simply measure up and pencil-mark the fan's four corner holes on the underside of the case, then drill 'em, drop some bolts through (they should have been supplied with the fan) and Bob's your uncle.
For the former, a more elaborate approach is required. Well, mostly glue. A two-part, metal-bonding epoxy is what you need, and for maximum purdiness you should pick up a fan grille too - you can find all this kit at any decent online case modding store. Lay the grille on top of the fan, drop the bolts through each of the corners, and apply the epoxy to the bolts' flat heads. Align the fan-grille array with the hole in your case, and stick the bolt heads to its underside. Then, affix some nuts and washers underneath the fan to hold it in place, and you've got yourself a stealth blowhole, with no ugly screw heads visible on the outside of the case. Hardly the be all and end all of modding, but this fairly quick n easy tweak does comprise many of the art's core principles. The same tools will cut holes to run water cooling pipes through, or create fittings to add carrying handles to the case, or etch a design onto its side, or create openings for front-mounted USB ports.
Alternatively, you could just buy a high-end case with a crap load of fan mountings. Standardized parts could be said to be taking the fun out of case-modding, but on the other hand they add a modular ease to designing a custom case. You could do something as simple as swapping out your PC's pre-fitted fans with LED-enhanced jobbies, and already you've got yourself a system that no longer looks like it came straight off a PCHyper Global Mega Mart shelf.
If you don't want to go down the boy racer route, perhaps your best option is painting. Whether it's simple re-coloring or an elaborate design of your own, it'll transform a metallic monolith into an item of pride, not shame. Car spray paint will do the trick, but be aware you'll need a primer as well as the paint - and don't mix lacquer and enamel paint and primer. Pick one and stick to it. If your case already sports its own paint job, you'll need to sand that sucker down first (which will likely involve dismantling the case into as flat pieces as much as possible). Removing the entirety of the paint isn't necessary, but you need to get rid of its texture. For this, you'll need some fairly heavy-duty sandpaper - 220 grit wet/dry, most likely.
Sand in just one direction, and ease off if you start to hit metal. You'll then need to move to a finer grain paper to smooth the surface off. Patience is vital - a visible scratch will stick out like a sore, gangrenous thumb come the painting and the primer's unlikely to fill it.
You'll also need to clean off the case before you start painting, as fingerprint grease and metal or paint crumbs will foul things up significantly. A spray can of air will get rid of the dust, and a quick rinse followed by a dry cloth rub will sort the grease. Then, it's primer time. The secret to this is multiple, very thin coats until the entire surface is evenly covered. Edges and areas where you've got a little too enthusiastic with the sandpaper may require a little more focus. Once the primer's dried, you'll want to go over it with a very fine (400 grit) sandpaper to smooth it off, and then you can essentially repeat the process with your paint of choice.
You could stop there and have a pretty decent-looking case, but, as tends to be the case with modding in general, there are levels yet beyond if you're in search of perfection. Specifically, a finish sanding with an even finer paper, followed by another color coat, followed by a clear coat to add gloss, followed by a rubbing compound to showroom-it-up. Each coat of paint can require a day or two to dry, and the total number of hours of sanding involved can approach double figures - it's a long job. Making something that looks decent or fixes problems like poor airflow or cluttered cabling is straightforward, but creating something unique is very much a different matter. You'll need to plan it minutely, measuring up every part and planned change, and not just plough on in and make it up as you go along.
Be prepared to trash cases, spill a bit of blood and accrue a vast collection of specific tools. Of course, with all that comes an enormous sense of pride - you're no longer a mere consumer. You're a craftsman.