If price isn't a concern, then for around $45-$50
1) Scythe Ninja
2) XP-120 with a quiet 120mm fan
3) TT Big Typhoon
For a heatsink that won't break the bank ($20-$25)
1) Artic Cooler Freezer64 Pro
2) Newer AMD Opteron/X2 stock heatsink (with 4 heatpipes) and a quiet 80mm fan
The first 3 choices may require removal of the motherboard from the case for installation, while the latter 2 will not.