I have the same cpu as you, so I know first hand lol. I bought the Arctic Cooling Freezer 64 Pro and it works great on this cpu keeping it cool. It's inexpensive too. My cpu at 3.4ghz right now stays under 30 C.
Newegg.com - ARCTIC COOLING Freezer 64 Pro 92mm CPU Cooler - Retail
if you want cheap and good, then that's the best fan. If you got more money to spend then get something a little better, but this one works fine for me. For our processor, you aren't going to find anything that will keep it much cooler, unless you get water.