Yes, Sam is right. Don't just buy a Custom HSF without verifying the standard of your default HSF. I am overclocking my Phenom II 955 up to 3.7 GHz with my default HSF without any over heat issue.
Now regarding gaming, Now 4 Cores are OK and a 785G mobo is also good choice. But when it comes to "future proof", probably, this is not ok.
The speed of hardware progress is so much and cannot be predicted completely . Now SATA3 and USB3 is in the horizon, probably the market will be flooded with these products in all of a certain in very short notice.
So better opt for a 890 chip-set based mobo, if not for a 6 core processor. It is lot future proof as you can upgrade the CPU to Hex Core any time you wish, and you also having the eye candy USB3, SATA3 etc from the begining.
Sam.Shab,pulsar_swift, piyush120290 and all the others, please suggest if I am justified.
Your config will be like
Amd phenom X4 955BE (B3 Stepping) @7.7k
PowerColor radeon 5770HD @9.6k (don't buy XFX 5770, I'm a sufferer)
Biostar's 890GXE board @6.5k
Ram 2 X 2 GB Kingston DDR3 1333 MHz (this one is having lower latency than the Transcend one) @ 5.4k
Cooler master elite 342 cabinet @2k
benq g2412HD ~ 10k
seagate's 500GB hdd @ 2.2k (price for Seagate 500 GB has been reduced)
logitech mk250 wireless combo @1.6k
ups + dvd drive @~3k