Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
MX Revolution. It's great as is, but it's better with SteerMouse.

Tried the Magic Mouse at work and I must say, it's good for 5 mins. After that, you realize it isn't ergo. and you lose expose and other customizing features unless you seek out third party. Odd for Apple to go backwards on this...
 
steermouse or controllermate are a must have for the mx revolution and performance mx. forget LCC.
 
My Mighty Mouse broke sometime last year and I started using a Razor mouse (model since discontinued) and I really love it and doubt I will try the new Magic Mouse unless I get a new Mac. If I need a new mouse, I would probably go for the Razer DeathAdder.
 
MX revolution has been by far the best mouse Ive ever Owned and Used.

Also use a little microsoft notebook BT mouse 5000.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.