The Kensington Expert trackball, at 11 years old — the second "serious" peripheral I ever acquired, after the Logitech Trackman (which I only disliked because of the lack of scroll wheel, but which I also still have in perfect condition), has come back into service. Felt a little sticky but that turned out to be a misaligned bearing, which I popped back into place (after 5 minutes of thinking I'd lost it when I popped it out) and now it's like butter.
The Logitech gaming mice are awesome, but there is something wonderful about a good trackball.
CST's L-Trac is very smooth but the scroll wheel is poorly positioned and the angle, plus the ball not being as exposed as on the Expert, hurts my wrist a bit: a more exposed ball means I don't have to rotate my wrist entirely as though I wanted my palm flat on the desk.
Maybe I'll try an Orbit one day.