In the age of the social networking explosion on the internet, I've never understood why some principles aren't being applied to things outside of websites.
I would love the ability to tag channels as 'sports', 'family', 'movies', 'steve', 'kara', 'crap', etc, and then be able to query the channel listings and tell it to display steve + movies + sports, or steve + sports, or sports + movies.
And do it by number, not station, so when something small changes on a shopping channel its tags (crap) still stick.