Mobo+PSU

1200 WATTS might be enough.
really I have no idea - and the uncore uses power beyond the rated tdp, so good luck.

personally I would wait for an amd 965 cpu. but you have money to spend on something I guess. why the 920? why not a 970? why 3 nvids? I just think you are growing your epeen. You need 30 fps in games. beyond that, you can't see it.

an amd 965 and 2 4890's would require an antec 800 signature psu, job done. run on an msi fx 70. with ocz platinum 1600 ddr3 7=7=7=24 amd edition ram.
probably half the price, and same performance.

sorry, I just want to tell you that - I don't mean to offend. call it a reality check and then do what you like. It's just that you have to ask about power consumption? so that says you don't quite know the monster you are creating. I apologize if this seems offensive. it's your money; or intel's. and I am saddened by the suggestion of support of antitrust - but that's a whole other story. I am sad. I am sorry. good luck; I hope it makes you happy.

^+1 (about both parts and comment)