Well, there are a couple of options for you.
They are:
SI-120,
9500,
and the (big) Typhoon.
You best bet would be the SI-120 as it offers as good as cooling as the others, but is easier to install. You would also need a fan for the SI-120 so choose a low noise and high CFM fan, which are pretty easy to find since the SI-120 uses a 120mm fan which are generally always quite enough and move plenty of air.
Even on a lower fan setting the SI-120 would still offer really good cooling.
Just make sure to use some Artic Silver 5 too. The temps will magically drop as it gets broken in.
BTW Thermalright make the SI-120. Zalman the 9500, and TT the (BIG) Typhoon.
-dragonx