I snagged this generic list and combined it from sites that listed HD content on cable. It isn't much better than E* at the moment. I don't think cable is compelling enough to warrant the switch just yet.
NBC
NBC broadcasts The Tonight Show, ER, American Dreams, Ed, Crossing Jordan, and Frasier, as well as primetime series Boomtown, In Laws and Hidden Hills. NBC executives have stated a commitment to producing a more significant portion of its primetime lineup in HD in the near future.
CBS
CBS has been the most aggressive about embracing HDTV, with most of its primetime programming airing in high definition. CBS has committed to increasing HDTV broadcasts. Among the series that will air, are: JAG, CSI: Crime Scene Investigation, Judging Amy, Without A Trace, Robbery Homicide Division, The District, The Agency, Hack, The Guardian, Becker, Touched by an Angel, Everybody Loves Raymond, Bram & Alice, Yes Dear, King of Queens, and The Young and the Restless.
Superbowl XXXVIII will be in Hi-def on Feb 1, 2004!
ABC
ABC is offering a greatly expanded line up of primetime programming during the 2003 season including Monday Night Football, NYPD Blue, The Practice, The Wonderful World of Disney, The Drew Carey Show, Alias, 8 Simple Rules for Dating My Teenage Daughter, and a large selection of feature films every month.
FOX and PBS also offer HD programming. Different markets have different availability.
HBO HDTV
Showtime HD
iNHD
iNHD2
Discovery HD
ESPN-HD
(This list isn't complete)