Tuniq Tower is THE best cooler for a C2D but they are hard to find. The best cooler for the money is Arctic Freezer Pro 7. I got one for 25 bucks and it keeps my E6300 under 55 at 3.2ghz on like 1.456 Vcore. If you want a better cooler (which usually you don't need) then get the Tuniq Tower as it is the best, but other than that the Zalman is good, so is the Scythe Ninja. As a matter of a fact just get any cooler since they will all keep an E6600 cool enough.
Still the Best is a Tuniq Tower, don't let anybody tell you the Zalmans are better becuase they aren't.
E6300 w/ Arctic Freezer Pro 7 @ 3.6ghz 1.4Vcore
Antec 900 Case
EVGA 750i FTW Mobo
4x1GB of G.skill DDR2-800
2 8800GT in SLI
22" Samsung Syncmaster
1 250GB WD and 1 Seagate 7200.10 in RAID 0
Corsair 520HX 3DMark06 Score: 13900