I would have said PBS HD, except that it is a 'local' rather than a 'national' channel. I am very tired of waiting for DISH to add PBS HD to its lineup. Comcast has it ...
TCM-HD by far, IFC-HD, BBCA-HD, AMC-HD but without all the commercials, Sun Dance, and never to forget the Voom channels (World Cinema, Film Fest, Kung Fu, Monsters, and Gallery, RIP). Doc and some of the Encore and Showtime additions would be nice after these. Let's drop many of the commercial-ridden channels like Bravo, Lifetime and its Movie outlet, and even TNT with TBS only slightly less annoying in recording size.
-Ken
Equator-HD was my favorite ... but unlikely ever again. So I have a choice of Smithsonian (don't know why it left) or ESPN-U. So I go with Smithsonian ... just because it is not available except in HD.
Some of my most favorite channels were on VOOM (like World Cinema HD, for example).
But they don't exist any more. Dish Network killed them...
Still, getting the remaining two VOOM channels would be nice though.
Other channels that I would love to see in HD:
1. IFC HD
2. Sundance HD
3. Arts HD
4. NASA HD
Not gonna happen anytime soon. ESPN's soccer rights have decreased after losing UEFA Champions League rights to Fox Soccer Channel. So there wouldn't be enough to fill an entire channel's worth of programming.
So my vote would be for Fox Soccer Channel HD when it goes live in January 2010.