I've been using Logitech's previous Anywhere mice in the living room to control a HTPC, but it's only been adequate, not great. This $US50 Couch Mouse might be very much better, because it'll work on a couch, bed or carpet.
The design looks about the same as their previous mice, but has hand detection, so it doesn't move unless you're actually touching it, saving on battery. The bottom of the mouse is also sealed to keep out couch/carpet fibres, and has an "easy-gliding base", but it's unclear what that means, since there are no photos of the bottom of the mouse.
But the main point is that it works on various surfaces (even clothing), which is good for mousing where you don't actually have a desk. Ships January.