Look Asus cards generally have aftermarket cooling.
Though, i would prefer Palit Super 8600GT over them. From, O/C capability to the temp range, Palit scores over them. Why? Credits to Zalman Cooling units over most of the Palit cards! MSI cards are nice too considering their low price tags. Just dont go for one with passive coolers!
Btw, 8600 isnt worth the money, considering better cards are available these days...i.e. 3650 & 3850, 9600GT. Priced little higher than 8600 though. However, better VFM!