DFI Lanparty 875P Motherboard. About $170 on average. Very stable motherboard, awesome amount of features, lots of nice accessories that come with it too.
Creative Labs Sound Blaster Audigy 2 Gamer if you're on a budget. Moving away from onboard sound improves your framerates quite a bit, and the quality increase is amazing.
Creative Labs Sound Blaster Audigy 2 Platinum if you wanna splurge and extra $100. It gets you THX-Select certified sound, forming a good base to use your PC as a home theater system.
Creative Labs GigaWorks 7.1 surround sound if again, you're going to splurge. THX-Select certified. 770 watts of power. It's loud, it's clear, it's humbling when turned up. The neighborhood knows when I up buffs...
I'm a big fan of Mushkin memory. The customer service is unmatched, the quality is great, and they're fast as far as memory goes. 1g of ddr400 cas2 memory will do you right, and it'll be a few more years before you'll have to upgrade again.
Get 1 Western Digital Raptor 10k rpm SATA harddrive at least. Either the 36g or 72g version. They're the fastest consumer harddrives you can buy, with seek times 1/2 of what people have now. I have 2 36g in mine. 1 of the operating system, 1 for installed games, and I put everything else on a 300g maxtor. It boots extremely fast, and well, runs everything extremely fast in general. The 72g model is marginally faster than the 36g though, but neither are expensive. Worth every penny imho.
Video card is personal preference. Some people are diehard Nvidia people, others are ATI people. I'm an ATI person, but that's because I burnt out a GeForce ti4200 from overclocking. Haven't killed this Radeon 9800 pro 256 yet, so they must be doing something right. Right now though, the GeForce 6xxxx series is the fastest out, even beating the ATI x800 cards. It really boils down to what you like & what you can afford. Make sure to read up @
http://www.tomshardware.com since they just released their VGA Review #5, which benchmarks every video card on there released to date
Monitors are kinda personal preference. I'll stick by my 19" viewsonic crt monitor. Yeah, it's a beast. I hate carrying it. However, it has a game mode which brightens up the colors amazingly, has some neat refresh rates, very low dot pitch, and was under $200 when I got it at best buy. Not the best I've ever used, but definately the best I've ever owned.
That's the major components, and I'll be the first to admit I cheap out on everything else like dvd burners, keyboard/mouse, etc.
Hope that helps!
-Indy007
Shiznots!