I've decided to stick with my original decision and buy a GTX 580, but I would like to overclock it as much as possible while staying safe.
So if you have an advice on which brand would be best suited for it, and how I should go about kicking it up while testing that it's safe to run.
I will include my PSU and CPU info incase you would like to know it,
CPU: Phenom x4 965 BE @3.4GHz (thinking of OC to 3.8GHz)
PSU: Silencer 750W (it's for a server)
Palit has fairly decent cooling, I'm not as sure on Zotacs quality though.
EVGA is a great choice when you're looking to overclock yourself.
Gigabyte is another good company due to it's cooling solution, but I don't think there's a twin fan cooler model yet.