You don't need to buy an expensive Radeon 6870. The base model will be just fine and you'll save a lot of money. In fact, I recommend XFX for ALL Radeon purchases, due to their double lifetime warranty (lifetime warranty for yourself + lifetime warranty for anybody you sell it to, increasing its resale value). Additionally, a 4 core 3ghz should be just fine for Skyrim, since it's doubtful it'll use more than 2 cores.
I don't know about Canada, but down here in Texas you NEED 2 fans on your graphics card. The summers here are absolutely ridiculous, we had 39 days of 100+ degree weather, only broken by a day of clouds and another 15 days of 100+. The extra cooling is worth it for me, and thanks for the reassurance about my CPU.