mousetype ?

wheels!

definately get one with a wheel. i have one with some sort of click thingy on top. you can push it up or down just like a wheel, but it acts as a mouse button as well. great for selecting weapons.

Mouse, mice, mace...

I've got a Logitech MouseMan Wheel, and I'm totally satisfied! It's got 4 buttons, a wheel (excellent for scrolling through the weapons!) and awesome ergonomics! Never before have I used a mouse that would let me play for an entire night without getting severe pain in my hand.
BUT, the most important thing is to make sure that the mouse fits in YOUR hand! Hands and mice come in varying sizes, so spend some time trying 'em out. After all, what good does "the best gaming mouse in the world" do you if you can only use it for 5 minutes at a time?
Good luck, and happy huntin'!