What's your price range and how much weight do you plan on supporting with it?
Those two factors will really change the answers
I use the Manfrotto 322RC2 Grip Action Ballhead and love it for it's fast manuverability, but it isnt the best for my bigger lenses.
For that, I'm saving up for the Wimberly which costs more than the dang camera body itsel http://www.bhphotovideo.com/c/product/3 ... lhead.html
There is the link to the 322RC2 if you want to look at which one I'm talking about