Best OS For Gaming! ?

Hi guys,

I have had my PC for a while now about a year and a half just recently SLi'd my 8800GTS 512mb to ready its self for future games.
My HDD now is full of crap and im planning to reformat my PC and was faced with the problem of which OS is better for gaming?
I currantly am using Vista Ultimate 64 but was wondering if Windows 7 RC was better? The problem i though about i may be faced with are drivers and programme compatibility issues.

Does anyone know which is better and why? thanks
Here are my PC specs Below just incase it makes a difference.

Processor: Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz (4 CPUs), ~2.4GHz
Memory: 4096MB RAM 1066hrz (4x1gb)
Hard Drive: 1x500 GB SATA II 7200rmp 32mb cashe
Video Card: NVIDIA GeForce 8800 GTS 512 X 2 SLI
Monitor: 22" Acer Widsceen 5ms
Motherboard: Asus Striker II Formula
Computer Case: Antec Gaming Case

Also for future of gaming and games do you think that the overclocking of my processor is nessisary? i was thinking if i OC it i would boost it to about 2.8GHz / 3.0GHz (case is fully air cooled)

Yeah maybe, im sure sum1 told me that when u use 7 the OS is more efficent and your FPS increases with out even doign anything to your PC ?

64 bit can't handle all games right? like some doesn't work or something.. but since you're preparing for the future I think you should stick to your 64 bit and possibly upgrade to windows 7 months after it's official release.