Budget build

[Evolv]

You could pick these up:
Newegg.com - OCZ Reaper HPC Edition 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory - Desktop Memory
Good ram that comes to $47 after MIR.

 

[Puddle Jumper]

I would go with the reapers.