You can... So your wish is granted.

At the moment, I have a laptop that I bought prebuilt (http://www.directron.com/laptopdiy.html to learn about how to build your own laptop). My old desktop on the other hand is kinda build by me. It started as a HP Media Center PC m7640n. Over time I replaced: the graphics card (NVidia 9600GT), the CPU/Heatsink-Fan combo (a AMD x64 3200+, gave it a silent fan), the PSU (a 600watt one I think), and the RAM (went to 4 gigs). This left unchanged the HDD, DVD-Rom, a tv media card that I never used and the motherboard.

I always build my own computers, the one I'm using now is only a few months old. Went a bit overboard with a SSD as a main drive, it is pretty sweet but not worth the money in the end. Maybe it will be next time I upgrade though, in a few years.

Building your own is simple as pie, you get instructions, just takes one evening and then you're done. Usually saves you money and gives you the specs you want.

I've built my own for the past 15 years, plus a couple for my girlfriend.

Did my first self-built PC recently.

Ditto, finished it in Jan

I build my computers. The only pre-made PC's I've had were the first two my mother bought for me and my bro. And that was back in the 80's.

After that, it was first my big bro who did the building and I watched. And after that I've built all my own.

I love building PCs, but more than that, I love filtering through pricelists for good hardware ;)

Me! me!

I remember it started back in early '98. I was nearly thirteen years old, and had bought Shadows of the Empire for the PC. I had played the Nintendo 64 version before on a store display model, and had enjoyed it tremendously (me and some other kids at the store had taken turns to play - got all way to the junkyard stage before I had to leave). So anyway, I inserted the disk in the old 120 MHz machine I had back then, ogled at the glorious screenshots during install, and then... "driver not found: glide32.dll". What tha hell?

I soon found out that meant I did not have something called a graphics accelerator. For the first time in my then short life, I couldn't play a game because I didn't have the correct hardware. That kinda sucked.
So, I started to research this strange new component I had never heard of, and discovered it was a card-thing I had insert into my machine (Wait, the machine got on inside?!). I ended up wishing wishing for money to buy this gizmo for my birthday. Got my wish granted, hopped on a bus to the city during the weekend (webshops? We didn't have no stinkin' webshops), and bought myself a brand new 3DFX Voodoo. Brought that back home, and learned through the manual, (and mainly trial and error) how to open the cabinet of my machine, carefully plunk in the card, fasten the screws, replace the cabinet cover. And then, with sweaty hands and pumping heart, praying I had not done something horribly wrong and the machine would blow in my face, I hit the power on button. It didn't explode!
The card worked beautifully once I got the drivers installed, and not only did Shadows of the Empire look even better than the version I had played on the N64, but I soon discovered my other games also got a massive visual boost if I selected my card in the configuration options.
So, from then on, I was hooked. I build my first machine in 2000 for the money I got in my confirmation ceremony. I have had two other built-from-scratch machines since then, both also build by myself. I think it's a big part of the fun with PC gaming; the machine is truly your own; your choices, your research, your game. Not saying prebuild isn't good or anything, but I can't imagine going back to that, its just more fun doing it myself.

Intriguingly, the machine I build two years ago is just as good now as then. I have not needed to upgrade it once, though I did swap out the graphics card with one that ran quieter and more efficient, but it was not a requirement in order to play new games, unlike my previous builds. In fact, I think the current generation consoles are probably one of the best thing that have happened to the PC hardware wise; you can get a pretty good gaming machine for a much less cash nowadays than... well... ever, I assume. And though that machine is still more expensive than consoles, it is not that large a gap any more, and you get a system that really can do everything. And then some.