I use a Kensington Expert Mouse. I have a bunch of different macros that I have written and can load depending on what I'm doing.
My default setup is just right click, left click, exposé and show and show desktop. Those cover most of everything fine, and I just use keyboard quick keys to do what I do.
If I'm doing music, I have a few macros that come in handy. I have one that can automatically do a replacement track for drums, or create a midi trigger track. I have one that can remove the sibilance from a vocal track and move it to another track to be eq'd and compressed differently (makes a HUGE difference!). Few others as well, but I don't remember them off the top of my head.