The Noctua NH-C12P CPU cooler and NF-S12B FLX Fan wound up being a perfect choice for the small form factor system I was assembling, and would probably be a great choice for many others. Considering that most high performance coolers would be way too big for a small form factor case, it was nice to see such performance in a more compact option.

http://www.bigbruin.com/content/nhc12p_1