I got the ZeroTherm Nirvana 120 for $49.99 back months ago. It's got a $20.00 MIR and free shipping right now, so you can get it for right at $30.
http://www.newegg.com/Product/Product.aspx?Item=N82E16835887011
ZEROtherm Nirvana NV120 120mm 2-ball UFO Bearing / Transparent CPU Cooler - Retail
Free mounting clip w/ purchase, limited offer
That keeps my OCed 720BE at about 26-28C idle, about 40-42C full load on 4 cores @3.4GHz.
Oh yeah...Arctic Silver 5 too...nuff said.