I voted for Keyclone as well. Top notch, simple product, great service ( I reinstall OS/format all the time, and have had no troubles get my license setup again within hours ). I have 3 copies so far and will be using Keyclone as long as I play wow.

I also use Innerspace. Excellent product and have been using Lax's stuff since EQ was the only real game in town. He also provides great service ( responds to issues/questions posted in IRC or forums very quickly )