Are you talking about a heatsink, or a heatsink/fan combo. Their are nice products on both ends, although if you go with just a heatsink, I've noticed that they run very very big compared to hsf units. Also, make sure you do some research and make sure that it will work well with your core2duo, nothing worse than buying a fan that's only been rated for Celeron processors...
Current Build (Hope to finish by late spring):
Intel Q6600 g0
Asus Maximus Formula
geIL Evo 2GB (2x1gb) DDR2
ATI HD3870 X2 or Nvidia 9800 X2?
2x 150gb RaptorX (Have it)
Thermaltake Toughpower 750w PSU (Have it)
Antec P182 Case
HP w2207 22" Monitor (Have it)