You'll want as many rails as you need, and obviously the higher the current the better. You'll also want one with enough connectors to power all of your equipment. Dual fan is probably better, with something sucking air out of the case. Antec and Thermaltake both make really good PSUs.
Intel C2D E6320 / AMD Athlon X2 3800+
Gigabyte 965P DS3 / DFI nF4 Ultra-D
2GB OCZ Gold PC2-6400 / 2GB OCZ Gold PC4000
eVGA 8800GTS 320MB / eVGA 6800GS 256MB
150GB Raptor / 74GB Raptor
2x500GB / 320GB
OCZ GameXStreme 850w / OCZ StealthXStream 600w