A 400W PSU should be more than sufficient: the biggest consumers of your computer are the CPU, HSF and the video card followed by the harddrives and the optical drives (when they are in use). The chassis fans arent a big concern since they are typically under 0.5W. 
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ASUS P5K Premium WiFi-AP, Q6600@3.7 / ASUS P5ND, E6400@3.8
4GB OCz Platinum XTC 8500 / 4GB CorsairXMS2 6400
5x500GB Seagate 7200.10 / 2x500 Seagate 7200.10
OCz 8800GTX 768MB @ 630/800 / 2x Galaxy 8800GT SLI
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