Access Micro has a AMD Athlon XP 2100+ processor, Asus A7S333 mobo along with a Thermalite heatsink and a Vulcan fan, 128 MB of DDR 2100 RAM for $216 shipped.

Newegg has a Radeon Atlantis 9000 128 MB DDR video card for $86.

Dealsonic has a really good mid tower ATX case with power supply for $40.

You are spending around $320 and getting a lot more for the buck.