I don't know if it is the king of performance, but Asus A8ne SLi/non-Sli edition should satisfy you. If u can get it, go for DFI LANParty NF4 SLI-DR. But I doubt u could in India.
AFAIK, all NForce4 motherboards support dual core processors, atleast after a simple bios flash.
You probably have wait for the power related query, but antec 400w shud satisfy most desktops.
Everything comes down to paper, really. How much can u shell out?