i would definitly order a thermal compond, unless it tell you with your heatsink that there is a thermal compound included, but then still it'll probably suck. Another question, do you plan on later crossfiring the hd 5770.
If you are then this set up will be fine, but if you don't plan on crossfire you might want to consider one of the lynnfield i7's, as you could save money on the mother board, then you wouldn't need 6 gb just 4, and you could also get a smaller power supply. all that together could be like $150 in savings
Junuxx... he is referring the OP possibly buying a 1156 platform. The only reason the OP is going with a 6 GB setup is because he's eying a 1366 platform. That said... the OP has already stated he currently possesses the i7-920 so his path is chosen. I don't think JonnyboyC fully read the OP's post.
The only thing I don't like about this build is the video card... 5770 ain't all that great of a card.
ohh sorry i read all of his components but failed to read the first line, O.o
Well still anyways, if you don't plan on crossfiring you could drop down to 600 possibly 500 watt PSU if you get a higher quality model, but again if your plan on crossfiring, then your system as it stands if fine