Personally if you are going to buy a card and then get a better cooler, just buy a GTS to start with. Already has a dual slot cooler, more SP, and OCs better (comes with a 0.05v higher GPU Core).
Other than that buy from XFX, eVGA, or BFG Tech. All have lifetime warranties, eVGA will warranty cards that were OC'd or had a cooler changed, XFX will transfer the warranty to the second owner... and BFG Tech has the best customer support ever.