qtirreco is a bit hit and miss, user submitted codes and dubious editor, i seem to have more success with set-top boxes than the tv's themselves.
TVbGone is a neat little widget for winding people up,
preenv lets you play some cool games, i loved the scummvm emulator and the new psx4m is pretty neat if you like gaming.
media wise i'm loving the new fuppes port that lets youi turn your n900 into a media server, wirelessly streaming to your home network, and you can already stream to n900 out of the box from a different media server.