I bet I'm one of the only ones here using a Trackball...
Its a Kensington Optical Trackball, wired, although I occasionally use my wireless Belkin when not directly infront of my machine.
I just like how I don't have to move it round, it has a defined space and never requires more. Also slows me down enough to allow the machine to keep up when I'm multitasking ;-) Yeh my PC could be better....
I got one Logitech 3button/wheel, one HP 3button/wheel, and the rest are Microsoft 5buton/wheel...I'm not sure how many of those I got around here. Oh and their all wired, I had a rechargeable wireless and it spent more time on the charger than in use (even after switching batt.'s) so it's now in some landfill somewhere.
MX Revolution (own 2)) by logitech and media mouse blue by logitech oh, and a wired mighty mouse i am soooo dying to replace with a nice but has to be white mouse !!!