OK, I gave in.

I took all the stuff back to Fry's and bought:
~ 4gb DDR2 PC6400 RAM
~ BFG GeForce 8800GT OC 512mb ($250 on sale at Best Buy!)
~ New MSI AM2 motherboard
~ AMD Athlon 64 X2 Dual-Core Processor 6400+ Black Edition (3.2ghz)

Upgrading/Repairing XP now... we'll see what happens

Wish me luck...