www.cyberpowersystem.com
They always have great prices here, and you can build your own PC.
I recently purchased a great system from them:
P4 3.0 gig, 800 FSB
512 MB PC3200 Ram
80 Gig HD
ATI Radeon 9600 Pro
19 inch monitor
Very nice case with neon lights
CD-RW (52X) and DVD-ROM (Both Sony)
Windows XP Home
....1300 dollars shipped.
I don't know if this is the right forum for this, but they always have great deals. And no, I don't work for them.