"I like the Logitec G5. Most of their gaming mice are weighted, have good ergonomics, are very precise and have a good "feel" to them. I also like the MS Sidewinder as it fills the hand well, and has good ergonomics despite sporting a pretty chunky looking design."
This is what I'm using, a friend recommended me to get one. It's a nice mouse, and it was a bit cheaper than other 'gaming' mice, I think.