The THERMALTAKE Thoughpower XT 775W (by CWT) is an excellent PSU. Anyway, if you are thinking about not doing SLI, the CORSAIR TX650 (by Seasonic) is a high quality PSU which has more than enough power to handle your system.
Concerning the graphic card, I would go for the ATI 5870 or wait until the GTX485. The GTX480 is an oven.
In reference to the memory, you have chosen two Dual Channel Kits. Taking in mind that your mobo supports Tri-channel memory, it is a pitty not to buy a triple channel kit like these ones: