New Gaming System - Opinions please

Hi all,

Well, I just ordered parts from NewEgg to build my dream gaming system. I
know it's not the "best of the best", but for under 2K I don't "think" it's
too shabby. Please let me know what you think...OR if I overlooked anything.
FYI, this is my first home-built PC...and I'm a little nervous after reading
about all of the compatibility issues with home-built systems. Oh well, I
guess the best way to learn is to dive right in. ANY advice or opinions
would be greatly appreciated.

ATRIX CSCI-A9001-C4 Black SECC steel sheeting FCC class CB&CE approved ATX
Mid Tower Computer Case (Vent panels on top and side - dual fans - good
airflow and front display panel for temps)
AMD Athlon 64 X2 4200+ Manchester 1GHz FSB 2 x 512KB L2 Cache Socket 939
Dual Core Processor
Antec TRUEPOWERII TPII-550 ATX12V 550W Power Supply 115/230 V UL, TUV, CB,
(2) eVGA 256-P2-N516 Geforce 7800GT 256MB 256-bit GDDR3 VIVO PCI Express
x16 Video Card
(1) Western Digital Caviar SE16 WD2500KS 250GB 7200 RPM 16MB Cache SATA
3.0Gb/s Hard Drive
(1) Western Digital Raptor WD740GD 74GB 10,000 RPM 8MB Cache Serial ATA150
Hard Drive
CORSAIR XMS 2GB (2 x 1GB) 184-Pin DDR SDRAM Unbuffered DDR 400 (PC 3200)
Dual Channel Kit System Memory
(1) 90mm Rear Fan / 120mm Side Fan / (1) ARCTIC COOLING Freezer 64 Pro
Cooling Fan with Heatsink for CPU

Note: I already have a monitor, keyboard, mouse, dual Layer DVD-RW, SB 7.1

A few questions/comments:
1. I was planning on using the Rapter drive for apps/games and the 250GB
drive for data. (any other suggestions for config?)
2. I know dual-core processors are NOT the best for gaming (yet), but to me
the pros outweight the cons. I'd rather be prepared for the future and lose
2 FPS at 1600x1200).
3. Depending on how well this case and fans cool, I may consider liquid
cooling. This case is so "open", I don't think that will be necessary.

Thanks all! I'll probably be visiting here again this week when all of my
parts get here and I'm pulling my hair out.