Phenom II 940 and GeForce GTX 280 - a good combination?

Hi,

I was wondering if the the GTX 280 would be 'held back' by the AMD Phenom II 940? Ideally I'd like the two to complement each other.
Also, I'm looking at buying these with 4GB of Corsair XMS2 800Mhz Ram. My point is that I don't want to be buying something that is ridiculously overpowered (or underpowered) when compared to other parts  
Finally, will triple copper CPU cooling be sufficient - or should I go for the Asus Silent Knight pure cooper?

Thanks in advance,

Pat