Sandy Bridge build for a friend

Hey guys
My friend wants me to build him a new system, and since I like doing that sorta stuff, theres no way I could say no. I'm not completely new to building computers (built my first around 4 years ago), but I am new to Sandy Bridge. If you think anything needs to be changed, tell me. It will be used for gaming primarily, and stuff like programming secondly. I will be overclocking to 4.0-4.5 GHZ.

Build is as follows:

CPU: i5 2500k, as I don't think the hyperthreading is necessary
GPU: XFX AMD HD 6950
Mobo: Asus P8P67 - Will it benefit much to get the Pro?
PSU: Corsair HX 650W - Do I need 750W?
CPU Cooler: Not sure... Prolimatech Megahalems or Zalman CNPS10X Flex
Case: CM Storm Enforcer
Memory: OCZ Intel Extreme 1600 MHZ 8-8-8-24 timings
HDD: WD Caviar Black 1TB 6 GB/s
Optical drive: Asus DRW-24B3ST DVD RW
Monitor: AOC 21.5" LED Full HD

What do you guys think?

Thanks