It's mainly personal preference to what you use, but personally I like
trackballs. Mainly the Alfa Data ones.
Though it's not a cordless device, you're not restricted by the cord becase you
don't move the whole unit like you do with a mounse.
Rather than moving your wrist or forearm to use it, a trackball only involves
moving your fingers.
Plus I find them more precise than a mouse for graphics work.