I'm a bit unclear on this one. He wants cable unbundled but then ends up complaining about the bad Comcast UI.

If you want ala carte cable you can get most every show you want via Amazon or iTunes, maybe with a Netflix and or Hulu plus subscription. Don't complain too much about the cable co's not allowing ala carte subscriptions, the large networks don't want you doing this either. They negotiate their carriage deals with large cable operators across all their properties so if you want Scripps Food Network you're going to have to get HGTV and DIY too..

If you want a better UI then look at GoogleTV. It ads a new layer on top of your existing guide to enhance the experience.

Also look at Comcast's Fancast and TV Everywhere initiatives (TV Everywhere is not Comcast specific) they are allowing subscribers to stream a lot of TV over the web negating the need for a Slingbox.