Oh, ok, that should be fine, and at least 400 watts output I'd say. I'd also recommend going with one of the more expensive makers (thermaltake, antec, ultra etc.), although they may cost more, they are far more powerful and reliable.
A lot of PSUs will label themselves as 400 watt or whatever, when this is actually their peak output. These more reliable brands pump out continous power, so when they say 400 watt, they mean 400 watt, not 400 watt max.
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