System configuration, HELP!!!

Hi guys! help me decide!

Q9550

evga 260gtx

asus P5E3 premium WiFi(ddr3) -OR- asus P5E deluxe(ddr2, same x48 chipset) =???

Corsair DHX ddr3 2x2Gb 1333Mhz -OR- ddr2 2x2Gb 800Mhz(depends of motherboard)

2x sata2 seagate 500Gb

PSU Corsair TX750w - OR - HX620w

Vista x64

Please help me decide with the board & ddram how much performance improve if I'd go with board & ddr3 ??, and I'm not sure about PSU is how much power will be ok for that system, what I know is 750 can deliver power till 900 and 620hx is very silent !!

Thanks for any help or opinion!!

I'd recommend a completely different setup. Get:

Intel C2Q Q6600 + Zalman 9700 heatsink

4GB of DDR 800 RAM

Gigabyte GA-EP35C-DS3R mobo

650W PSU

Radeon HD4850 (Gigabyte, MSI, Sapphire are great brands)

Windows Vista Home Premium 64-bit

You'll save more than $200, yet receive the exact same performance. Trust me, there is less than 1% performance increase between DDR3 RAM and DDR2 RAM.