if you're only doing mild overclocks, the best budget performance cpu heatsink is the coolermaster 212plus.
ncix has it for $29, but you can pricematch it down to $22.
great reviews on it, check it out on overclock.net too!
http://www.ncix.com/products/index.php?sku=41337
pricematch:
http://www.bestdirect.ca/products/21...R_B10_212P_GP/