If you have no intention of overclock even the stock fan would suffice. But if you want a better guarantee and quieter performance I'd go with an ok after market air cooler.
The cooler master v8 remains as one of my favorite mid-high end coolers... although for no oc it might even be a bit of an overkill. It costs about $50 on newegg.com http://www.newegg.com/Product/Product.aspx?Item=N82E16835103055
The v6 is not too bad... there are really a lot of coolers out there... most after market coolers for $35 and up will be not too bad.
They will cool a lot better than the stock cooler and look cooler too lol... which is a plus even if you're not overclocking... Hope this helps