Go with the regular P5E, DDR3 is pointless on a Intel FSB based platform because the higher bandwidth is just bottlenecked by the FSB. For example, if the FSB is running at 333MHz (= 1333MHz quad pumped), then running the RAM above the speed of 333MHz (= 667MHz DDR) is pointless, because the FSB will restrict the RAM.
Go with 4GB of DDR2 800, so you have some room for overclocking on your Q6600.
Coolermaster RealPower 700W Modular PSU
I'm not a big fan of CM PSUs, I would look at the equivalent Hiper Type-R model.
Also, Antec 900 sucks ass