I've adopted an XBOX 360 controller setup (w/ Chatpad) via Xpadder that has become my preferred PC input device. It doesn't replace the KB/M for FPS's, but it really excels w/ RTS and 3PS's.
"You know what the chain of command is? It's the chain I go get and beat you with 'til ya understand who's in ruttin' command here."
- Jayne Cobb, "Firefly"