Motherboard is partially a component and partially a connector. Everything goes through the motherboard, and the motherboard has its own shit. It's also one of the only things different between AMD and Intel. Originally there was a mini-cpu called a Northbridge that I'd have difficulty explaining but not so much anymore since the market thinned out a lot. Suffice to say the "chipset" of a motherboard, whether it's an Nvidia Nforce or an Intel X58, is still somewhat important.
What's also important is the "power phase" of the mobo. Asus for example is known for making high-phase motherboards: Meaning they suffer from less "vdroop", a dip in the power supplied to the processor when under strain, than other mobos. It's a better overall design basically.
You also used to need to worry about your capacitors and so on but except for foxconn and macintosh pretty much everybody uses solid state capacitors and is rohs compliant now.
Just stick with Asus or Gigabyte and dont get nvidia chipsets and youll be fine until you understand it. This takes longer than most other things to "get" when learning computers, partially because it keeps changing.
Think of ram like a desk and a harddrive like the drawers under it. Ram is how much you can have on your desk and work with cleanly at once, and when you run out you need to start constantly putting things back into the drawers which takes forever, and when you REALLY run out you start clumsily working in the drawers too instead of just on the desk. That's exactly how RAM works.
For now just remember that Core i7 processors are triple channel, meaning buy in multiples of 3 (3-6-9) and everything else is dual channel so buy in multiples of 2 (2-4-6). The speed of your ram will almost NEVER make a difference, I buy pretty much the slowest reliable ram out there and I get the same FPS as people with $400 ram. The only time that, or CAS timings (the numbers that say "5-5-5-15" for example) make a difference is during competitive overclocking competitions, for us mere mortals who dont cool their computers with solid oxygen it's just internet-penis-measuring.
Corsair, Geil, Gskill, Mushkin, and OCZ are all good ram. Heat spreaders (looks like fins or a heatsink on the ram) are nice but mildly functional at best and really only a marker of when you start getting into the decent stuff. Just look for the customer choice award thingy on newegg or get what one of us says and your probably fine.
CPU - Central Processing Unit. Has multiple cores, is 64bit (there are no more 32bit processors made), may support hyperthreading if its an Intel. As you learn more you get into L2 Cache, SSE support, clock speed and multipliers and the like but for now more L2 Cache is better on Intels and more ghz is better.
Intel generally splits there processors into 3 lines: Stripped down with slower speeds and HALF the L2 Cache, Ordinary with the full amount of L2 cache and normal speeds, Extreme Edition with barely higher speeds and maybe a tad more L2 cache but an unlocked multiplier. EE's, jokingly called Emergency Editions, are for competitive overclockers exclusively. Don't waste $1000 on a processor, $300ish is usually the sweetspot on newer releases.
Generally the highest benchmarking processor in your price range is going to be the best bet, it'll usually be a clear winner and tends to be conspicuously popular like my "Q9450" was a few years ago and the Core I7-920 is now.
GPU - Graphical Processing Unit. Originally these had dedicated pixel pipelines and various processors but now they're all unified architecture, ATI or Nvidia will have a given number of Stream Processors (different name from each company ofc) and then they'll have a given amount of ram and a given bandwidth.
There are patterns to buying a good one, but suffice it to say that $250-300ish is the sweetspot and always wait for the SECOND revision of a new line of cards since there's usually a kickass midrange card included in there at a decent price (my GTX 260, the 8800GT...).
The real trick is basically bandwidth, not ram. I used to game at 1600x1200 with a second monitor running and I didnt use up 500mb of my 8800gt's memory. Plus, all the memory on your graphics card gets "stolen" out of your system RAM because of bad decisions made back in like the 60's and 70's before windows even came out.
The best graphics cards are the ones that combine decent clockspeeds, good numbers of processors, and high bandwidth. These are the guys that will have a solid framerate even when you raise the resolution even if all their framerates in benchmarks aren't necessarily as high as others. Cards to avoid are ones that get a high framerate but drop quickly as you raise the resolution or start using AA and AF, a good card will give you a steady framerate across multiple resolutions and AA/AF settings.
Speaking of which, set Anisotropic Filtering (AF) at 16x and forget about it. That has been effectively "free" since about 2002 because it takes so little processing power. It'll take a bit to get used to having clear and crisp textures out to infinity but you'll grow to like not feeling like you need glasses when playing a game, and it helps with seeing shit from far off.
XFX and EVGA are the "big two" of videocards because they offer excellent customer service and lifetime warranties. XFX goes so far as to allow you to replace the heatsink with a custom one and to extend the lifetime warranty to whoever you sell your old graphics card to.
A top of the line single-gpu gaming computer with a lot of hard drives in it uses about 300-400 watts at its highest peaks. It's not the watts, its the amps. Corsair, PC Power and Cooling, and Seasonic power supplies are known for reliability and specifically for giving rock solid amps.
I think it was the 550 watt corsair that had FIFTY amps on the 12v rail, compared to an exploding off-brand power supply (again, not joking, exploding is LITERAL) having maybe a dozen tops.
I know your gonna cheap out on the PSU anyway but still, read Jonnyguru to see why those three brands are important.
Water cooling = air cooling now, active cooling is dangerous and difficult due to condensation, and just get a Noctua UH-12P or a Thermalright Ultra 120 Extreme like the rest of us because really there's no contest about what the best heatsinks are and there hasnt been for nearly a decade now. 120mm fans are quiet, anything smaller gets very loud very fast, even an 80mm fan is REALLY loud compared to the vague whispery whooshing noise of a 120mm fan. Yate Loon fans are great and quiet, Delta fans are called "screamers" and can break bones and tear flesh (im not kidding, dont stick your finger in one), and Noctuas are dead silent but have very poor airflow.
Now... I need to go to gainesville for the day so I'll probably not be back for hours.
