Right, I have mine hooked up to a fan controller. I have it set to 1900rpm, so realistically, I could have gotten the 2000rpm version.
BUT.... I do have the option of going 3000rpm if I wanted to for benching a high overclock once in awhile.
So, if you don;t have a fan controller, get the 2000rpm. If you do have a fan controller, get the 3000rpm one since you can turn it down or turn it up. They are usually the same price too.