So you are rewiring your PSU fan and plugging it into the 3 pin motherboard connector if I understand correctly? I don't really see the point to that as you'll void your PSU warranty and have excess wires hanging everywhere.
The only two which are required are the 24 pin ATX 12v and the 4 pin ATX 12v. If you have a spare 4 pin molex connector I'd recommend plugging it in just so your parts have supplemental power, but that's really only there to feed more power to overclocking enthusiats who are pumping a lot of voltage. The FDD is again unneccesary unless you are running SLI, but again, for stability if you're not using the FDD molex for anything else it will not hurt.
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