New MB

Yes any 1366 motherboard will do fine. Thankfully Gateway Dell or any of the other mass production computer companies cant mess up the CPU with limitations and what not.

is the OS a gateway copy or new?

The OS is from gateway (win vista) but i will be going to Win 7 64 bit, replacing the HD when i do

Suggest:

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

And if you gonna OC ...might as well do this at the same time. Check to make sure your case has enough room for tall HS

Heat Sink - For performance and ease of installation, the Prolimatech Megahalems fits both criteria. Here's what I'm putting in new builds Mega w/ IC Diamond TIM and twin Scythe PWMfans (make sure ya MoBo can handle the fan wattage). ($65 for the HS, $7 for TIM, $11 each for two PWM fans and $7 for a Y cable splitter))

http://www.frozencpu.com/products/8807/cpu-pro-01/Proli...
http://www.frozencpu.com/products/7038/thr-41/Innovatio...
http://www.frozencpu.com/products/10026/fan-639/Scythe_...
http://www.frozencpu.com/products/8418/cab-150/FrozenCP...

If that's a budget breaker, look at the Xigmnatec S1283 or one of the others here:
http://www.silentpcreview.com/Recommended_Heatsinks
http://www.frostytech.com/top5heatsinks.cfm#INTELHEATSI...
http://benchmarkreviews.com/index.php?option=com_conten...

pick a TIM from the top few here:
http://www.hwreviewlabs.com/index.php?option=com_conten...
http://www.xbitlabs.com/articles/coolers/display/therma...
http://benchmarkreviews.com/index.php?option=com_conten...