I agree with the Thermalright xp-90C being the best.
I personally have a xp-90C paired with a 92mm vantec tornado. Very loud fan but great at cooling. If noise not a issue that what I would get. only thing to check is make sure you have enough space in your case for a 92mm vantec tornado because they are taller then most 92mm fans.
If you dont want to deal with the noise of the vantec tonado 24/7 then you can do what I did and get a fan controller. When am not using the computer I keep the fan on it lowest setting (about 2400RPMS) but when I gaming I turn it up to max (about 5000RPMS). I recommend the VANTEC NXP-205-BK fan controller if you want to get a fan controller for it.
So do I, but a note of caution however. It is very heavy. I would not trust something like it hanging off my CPU, thus I have an XP-90. Plus, it's almost twice the price as the XP-90, and there is only a difference of 2C at most.