I found a good deal today when I went to order the custom built PC on the front of the CC ad. It was advertised for $299 AR.
When I went to the Kiosk to build it lets you add and delete what you want.
Starting with the baseline model Presario SR1000Z (CPQ PUO26AVABA)
AMD Sempron 3000+ Processor 2.0GHZ
Upgrade to Athlon XP 3200+ for 20$
256MB DDR/PC2700 (1 DIMM)
80GB 7200 rpm Ultra DMA (+10)
48x max HP CD-Writer
Anyway take off the monitor and speakers and you can get this system for around $200 AR plus or minus what bells and whistles you want. It's a 200 Rebate from Circuit City and a $50 rebate from Compaq.
Edit: You now have to purchase the monitor to get the $200 rebate along with an additional $50 rebate from Compaq. Kills the great deal.