I switched to BOINC for my main computer because of the awesome ability to turn off GPU crunching while the computer is in use.
My primary folders are my research lab PC and "HTPC" folding 19:00 to 07:00 daily. It's crazy how much the SMP bonus is affected by not doing 24/7. If they Folded 24/7 I'd get about 9-12k PPD, but folding 12h/day is getting me less than 4k PPD.
EDIT: If you're wondering how I do the 12 hours a day thing, I use Task Scheduler. I tell Task Scheduler to start fahclient.exe at 7:00 PM + allow it to wake the PC, and stop it if it runs for more than 12 hours. With sleep mode set up, the nocturnal computer wakes up, folds, and then sleeps again in the morning.
"The computer programmer says they should drive the car around the block and see if the tire fixes itself." [src]