For those aging gamers out there - thought I'd mention this one. This (picture) is the mouse I use, and I find it's helped stave off some carpal tunnel.
The mouse feels a little weird at first, but after awhile, you get equally proficient with it - I even switch between this one at home, and a normal mouse at work, so that I work different muscles in my hand. I haven't experience a lot of wrist pain since doing this (and some regular stretching).
So... forget that Razer mouse or whatever fancy things are available now, and try this weird-looking but effective mouse. Comes in wireless with more or less buttons, too.