one of the interesting tools I occasionally use along side my mouse that I'm willing to bet not very many use-- a LogiTech Rumblepad and an Attack Joystick. The software that comes with them allow them to be configured for any application, and the cursor speed can be fine tuned or limited seperately on each control stick and seperately from other devices. So, when I need pixel perfect control/movement, these devices serve me exceptionally well. And with about 11 - 12 buttons each they can also be programmed to quickly trigger actions, events, a series of macros, etc.
Though, I don't need their cursor control functions often, most of the time, they're make excellent one touch HotKey devices.
I can be somewhat of a device freak-- even my mouse has 14 functions.
I don't use a tablet, but it is on my list though. I think it would make a fine addiction, er, addition.