Fortron/Sparkle all the way. I've got a FSP350-60PN, and it is awesome for the money. It runs my media PC (2GHz celery at 3.2GHz) with true ease. I have seen the FSP300-60PN drive a lot stiffer loads than you propose, so I doubt there is really any reason you would need to opt for the 350. Surely the 120mm fan makes these some of the nicest power supplies made, and the clear winner in the low-bucks department.
BTW-I've got a friend that has a P4-3.0c on an 865 board with 1GB of ram, a Ti4200 video card, 2x80GB HGST 7k250s, two old IDE drives, DVD burner and various small stuff all running happily of his Sparkle 250. It is only rated at 13a on the 12V line, but has no trouble at all with his 12V-centric load. In light of this it's hard to imagine your folding rigs exceeding the load driving capacity of the (vastly improved) FSP300-60PN.