a really good air cooler for cheap is the cooler master hyper 212 EVO...it performs amazingly for the price only a few degrees C warmer than the best of the best and a third of the cost....unless you are going for the absolute max OC out of your chip then you will not notice the difference in performance...but you will notice the difference in the cost and size (not saying the evo is small by any means)
http://www.newegg.com/Product/Product.aspx?Item=N82E16835103099