on my htpc i mainly watch movies and play n64 and snes games....
I have the ATi Remote wonder... it's OK, not perfect... Plenty for watching movies and controlling most functions.
Occasionally I'll need better control so I have a logitech cordless optical trackball and logitech's wireless keyboard. Most the time the keyboard stays under the end table though.
For gameplay I have a USB gamepad made by saitek with a belkin USB extension cord. Looks and feels similar to a playstation II controller. A wireless controller would be nice, but I couldnt find anything acceptable.
All remote devices run on rechargable NiMH batteries.
One of the remotes that I hrought were interesting was the remotes that come bundled with snap stream. I thought the control and interface of snapstream was really nice, but there were a few bugs and performance issues when I tried it.