My current favorite ballhead is a large magnesium Gitzo whose model number I forget. It's very smooth, locks tight and didn't cost a fortune. I set it up to use the Bogen/Manfrotto big hex head quick releases.

Bogen/Manfrotto makes a wide range of ball heads that are not expensive. So does Giotto. The main considerations for ballheads are that they move smoothly and lock up tightly. For serious macro use, a geared head may be preferable but you can also fit a focus rail to a ballhead that will enhance adjustability.