We use a £12 remote control to operate xbmc. Fundamentally, up/down/left/right, OK and VCR controls (pause/ff/skip/stop) are all that is needed.
Once set up (by you - and that may take a little time

) xbmc is by far the easiest interface to use IMHO. The box boots into xbmc and you are in a media player without even knowing you are running a PC underneath. We have a list of unwatched films, all populated with IMDB info to choose from by default on the movies page. The TV page just has a list of programs and when you enter a particular program, it is broken into series together with a tick next to the episode if you've watched it. Pressing play on a partially watched movie/TV episode just asks you if you want to start from where you've left off or start from the beginning. Not only that, the UI is the same on all 3 boxes and I can partially watch a film/episode on one box, stop it, move to another and it will ask me if I want to resume from where I had stopped on the other box.
Audio is always supplied by the TV, so no need to swap inputs on the amp either. Input 3 -> xbmc, Input 4 -> TV.
Simples - as I believe the kids say these days