There's a new XBMC plugin for TV shows, that's been working really well for me.
TVOnline. It's just TV shows, but it works great and it's really reliable. You don't have to pick sources, it doesn't buffer, and the selection is good. This plugin is new, so future development will make it even better. You can subscribe to shows, and they'll show up in your library and new show will be added to your library automatically when they come available. It's pretty solid.