New Gaming PC Build, any last suggestions?

I have been doing much research as this is a big purchase for me (spending a MAX of $1600, but $1500 is the ideal price limit). It is being built for mostly gaming. I always browse the Tom's Hardware forums for everything that I need to find. I figured since I now have the money to spend, I'd make sure everything I researched is good. I also would like to avoid silly things like the heatsink not fitting the case.. Also to know the money will be well spent. Any input will be greatly appreciated!

Case: Antec Nine Hundred Black Steel ATX Mid Tower Computer Case

MoBo: ASUS RAMPAGE FORMULA LGA 775 Intel X48 ATX Intel Motherboard

Video Card: VisionTek Radeon HD4870 (Plan to CrossFire in the future)

PSU: CORSAIR CMPSU-750TX 750W ATX12V

Ram: G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066 (Plan on POSSIBLY upgrading to more)

HDD: Seagate Barracuda 7200.11 500GB (Planning on adding another)

Heatsink: Sunbeam CR-CCTF 120mm "Core Contact Freezer" CPU Cooler (Changed from Zalman)

OS: Microsoft Vista Home Premium 64-Bit

CPU: Intel Core 2 Quad Q6600 Kentsfield 2.4GHz 2 x 4MB L2 Cache LGA 775 Quad-Core Processor
OR (If my next paycheck is decent [which I don't think it will so I'm 80% going with the 2.4GHz])
Intel Core 2 Quad Q9550 Yorkfield 2.83GHz 12MB L2 Cache LGA 775 95W Quad-Core Processor
(Either of which I plan on OCing to whatever is safe, on the cooling that I'm purchasing.)

Are there any final thoughts, I've been told before that it's a very solid build, the build looks nothing like I originally built, I went from Core 2 Duo, to Core 2 Quad, and from NVIDIA to ATI, it's been a long road but I just want to get it over with, and be sure after all the waiting/ researching that it is worth the money spent. So if it's not too much to ask, any input will be greatly appreciated!

http://www.frostytech.com/top5heatsinks.cfm

Here's a better one.
http://www.newegg.com/Product/Prod [...] 6835207004

Thanks so much for the info. The Heatsink actually has been what I've changed the most, I think I'm going to go with the Sunbeam.

I think I have a couple more dollars for my build, would it be more logical to spend it on upgrading from a 4870 to a 4870x2 or just going with the 2.83GHz Quad Core, instead of the 2.4? or should I even consider holding out and getting both? Is the step up from the 2.4 to 2.83 even worth it? I plan on OCing the 2.4 but still am not sure if I want to risk it.

With sse4.1, q9550 can outperform q6600 by 30+% per clock! But only the newer encoding software use it, not even the older ones. So for gaming, it doesn't really matter.

For gaming, going down to q6600 and use the savings for x2 will definitely give you a large performance boost. Q6600 ocs well, so you can easily run it past a stock q9550 anyway.