logitech :: cordless trackman wheel mouse
When you do a lot of fine pixel work with a mouse, easy control is a must. This mouse doesn't get stuck or become erratic. You can turn the sensitivity way up, as your thumb is more capable of fine movements than your whole hand. It's also great for people suffering any RSI as it's a different range of movement to using a regular mouse. Has the standard features you would expect, track wheel, two mouse buttons, and it is available wireless.