At home, I have an ancient (4+ year old) Logitech MouseMan Cordless Optical. I love the thing, except that it requires 2 AA batteries and doesn't have a built in recharger.

When I travel, I usually use either the trackpad or carry a corded optical mouse with my laptop.

The trackpad is usually good enough for whatever I have to do on the plane, and the corded mouse is one less thing that could go wrong (mainly batteries die in the mouse) when I'm on the road.