Need some input on my very first home-built PC!

Hey everyone, so I'm building my very first PC and I'd really like some help and/or criticism on what's good and what needs to be changed in my setup! I will be using this PC for MMO gaming and general everyday use.

What I'd Be Ordering:

AMD Phenom II X3 720 2.8GHz Socket AM3 95W Triple-Core Black Processor Model HDZ720WFGIBOX

Scythe SCKTN-3000 92mm Sleeve "KATANA3" 3Heat Pipes CPU Cooler - Retail

ASUS M4A78T-E AM3 AMD 790GX HDMI ATX AMD Motherboard

mushkin HP 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Dual Channel Kit Desktop Memory Model 996659

Western Digital Caviar Black WD5001AALS 500GB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive

SAMSUNG DVD Burner Black SATA Model SH-S223L LightScribe Support

Microsoft Windows Vista Home Premium SP1 64-bit for System Builders w/ Tech Guarantee

What I Already Own

2 ATI Radeon HD 4850's (to run in Crossfire)

700Watt Rocketfish Power Supply from BestBuy

Antec 900 Case

HP w2007 20" LCD Monitor


So how's it all look? Anything I should change or any compatibility issues I need to address? Anything I missed? I'm new at this whole PC building thing and would really appreciate any input you'll give me. Thanks!

Alright swapped out the ram in my Newegg shopping cart.

I think I'm going to stick with the 500gb Caviar Black because there's a good member discount on it (unless the 640gb is faster?).

Is my Rocketfish PSU insufficient? If so I'll gladly return it and get that OCZ or something similar.

It's just generally a good idea to go with a high quality psu since its feeding power to all of your components.

A poor quality psu can damage your system, and ocz is quite a reputable brand.

I'd say if you can return the rocketfish one, you definitely should.