My personal workload is negligible. The best box I own is a Celeron with 256 MB, overclocked to 300 MHz. At work, I can borrow a machine or two when they're not busy doing "real work," so a folding client like notfred's where all the work stays on a USB stick is ideal.
1 instance on a 3 GHz Prescott with 1 GB of RAM
3 instances on a 3GHz Dualie Paxville with 2 GB of RAM (I may replace this with a single SMP client shortly)
Today, I've got 3 GHz x 8 cores and 16 GB of RAM I can play with, but I've gotta give it up tomorrow. Tomorrow, who knows what I'll have?
Looks good, don't worry, whatever you fold is definitely worth..