I'm looking to build a gaming PC from scratch for about $1500. I've never built a computer on my own before so I'm looking for advice and warnings in case I'm about to screw something up royally. Here are the components I picked out so far:

Case: Antec Nine Hundred Black Steel ATX Mid Tower Computer Case - Retail
http://www.newegg.com/Product/Prod [...] 6811129021
It got great reviews on all the sites I've seen and I kind of like the LEDs. It'll be in my living room so I don't care about the extra light and I'll probably be turning it off or hibernating when I'm not using it anyway. It's going to rest on the floor so having the front inputs be on top should be handy.

PSU: ABS Tagan BZ Series BZ700 700W ATX12V / EPS12V Patent Piperock Modular Power Supply - Retail
http://www.newegg.com/Product/Prod [...] 6817814015
The 800W version of this got great reviews as well and it looks pretty cool. Since I have that window in the case, I might as well make the insides worth looking at.

CPU" Intel Core 2 Duo E8400 Wolfdale 3.0GHz LGA 775 65W Dual-Core Processor Model BX80570E8400 - Retail
http://www.newegg.com/Product/Prod [...] 6819115037
I'm going to be gaming mostly so the quad cores are a waste. This is supposed to be easy to overclock so that's good for a first time OCer like me. Great price to performance. The $60 extra for the E8500 just doesn't seem worth it when it's supposed to go up to 3.6GHz easily on the stock cooler.

GPU: MSI R4850-T2D512 Radeon HD 4850 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card - Retail
http://www.newegg.com/Product/Prod [...] 6814127359
It's getting great reviews and benchmarks. I liked this better than than nvidias 9800GTX because I kept hearing bad things about nvidia's 6xx and 7xx motherboards and I want the motherboard to be made for the GPU I'm dropping all this money on. I'm going to wait until the 4870 is out and reviewed before I purchase in case that's worth buying instead. I'm willing to spend another $100 if it lives up to the rumors. Alternately, I may get a second 4850 and xfire them if I start craving more speed.

RAM: CORSAIR XMS2 DHX 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model TWIN2X4096-6400C4DHX - Retail
http://www.newegg.com/Product/Prod [...] 6820145194
This one I'm really unsure about. It got decent enough reviews and the Corsair website recommends them for my motherboard, but there are just so many choices with RAM that I kind of just picked this one randomly. I know I won't get the full 4GB with the 32bit version of vista. I'm fine with only getting 3.1-3.5GB used. It doesn't seem worth dealing with software compatibility issues that I've read about to go to the 64 bit version.

Optical Drive: Plextor PX-810SA/IBP-BL DVD Super Multi Drive - 18x DVD±R, 10x DVD±R DL, 12x DVD-RAM, SATA
http://www.tigerdirect.com/applica [...] u=P67-1310
Plextor has been good to me so far and I want something reliable, quick, and of good quality.

HDD: Seagate Barracuda 7200.10 ST3500630AS 500GB 7200 RPM SATA 3.0Gb/s Hard Drive - OEM
http://www.newegg.com/Product/Prod [...] 6822148136
Another component I'm not too sure about. I want something fast and at least 500GB. I hear that Seagates are good.

OS: Microsoft Windows Vista Home Premium SP1 English NA Upgrade DVD - Retail
http://www.newegg.com/Product/Prod [...] 6832116470
I picked Home Premium over Ultimate because I don't have any need for the networking. I have a copy of Windows XP Professional so I think the upgrade version should work from a clean installation. I picked vista because this rig should have enough power to handle it and I want the DirectX 10.1 features.

Monitor: Acer P243WAid Black-Silver 24" 2ms(GTG) HDMI Widescreen LCD Monitor with HDCP Support - Retail
http://www.newegg.com/Product/Prod [...] 6824009125
Great reviews. Good price/performance. Wanted a 24" to take advantage of all the power I'm putting into this thing.

That all comes out to a little under $1500 before tax and shipping. I prefer newegg because I live in So Cal so shipping will be very quick to me even with the 3-day shipping option. I could also use some advice on a gaming mouse and keyboard combo. Are there any good wireless options? I'll have my computer next to my 46" 1080p LCD TV so I may hook the system up to that occasionally and try playing from my couch. I guess I could just get USB extension cables too since I'll usually just be at my desk. Also, should I get a fan for that side vent bracket in my case? If I should, what do you suggest? Am I missing anything? Thanks to everyone who helps!

how about a motherboard?

I'd go Vista 64 if I were you. dual boot with your XP32

assuming your going to be using this for a year or more, quad core wont be a waste for games.

get a 7200.11, its faster. I'd get more that 500 especialy if you take the dual boot advice.

Oops.. knew I forgot something...
Motherboard: GIGABYTE GA-X48-DQ6 LGA 775 Intel X48 ATX Intel Motherboard - Retail
http://www.newegg.com/Product/Prod [...] 6813128331
Also got great reviews.

Any suggestions on what 7200.11 HDD to get? I didn't even see that alternative.

Interesting suggestion on dual booting? Are there any risks with going 64bit that I should be aware of? It'd be kind of a pain to have to reboot to use certain software. Especially if I want to use software together than only runs on one or the other.

the only software I cant run on Vista64 also doesn't run on Vista 32.