$500 Build

This system can play older games on high settings and should support new games on moderate settings.

AMD Athlon 64 X2 4400+ 2.3GHz (Brisbane) Socket AM2 CPU - $85
- out-performs similarly priced dual-core Intel CPUs

Gigabyte GA-M61P-S3 Socket AM2 motherboard - $80
- good feature set on a budget: gigabit ethernet, 8-channel audio, firewire
- on-board GeForce 6100 graphics make for a nice backup

G.SKILL 1GB DDR2 800 (F2-6400CL5S-1GBNQ) RAM - $40
- flexible voltage range, 1.8-2.0V

Western Digital Caviar SE 160GB (WD1600JS) OEM hard drive - $50
- 7200RPM, 8MB cache, SATAII

XFX GeForce 8600GT 256MB PCI-E video card - $120
- DirectX 10 support

Fortron AX400-PN 400W ATX power supply - $40
- reliable brand
- top quality for cheap

Lite-On 16x DVD-ROM (SHD-16S1S-05) OEM optical drive - $18
- black, SATA

Cooler Master Centurion 5 (CAC-T05-UW) ATX mid-tower case - $50
- black, very basic
- includes 120mm and 80mm fans

GRAND TOTAL = $473

Wiggle Room

If you don’t need the case and/or optical drive, I'd recommend another gig of RAM; you can get a dual-channel pair of the G.Skill DDR2 800 RAM for $75 (F2-6400CL5D-2GBNQ). Or you can double the hard drive space for an additional $30 with something like a Seagate Barracuda (ST3320620AS). If you insist on exchanging DX10 support for more graphics performance, a Radeon X1950 Pro card would do very nicely for around $150.