If you have an HBO and a Showtime subscription, you can get those in HDTV. A surprisingly large amount of their programming is simulcast in both standard-def on their main channels and hi-def on their hidef channels. For the HBO/Showtime shows which do not have a hidef print available, they broadcast an up-converted regular-def show with black side bars.

If the TV stations in your local area have hidef over-the-air broadcasts, you'll get those. (That's called "OTA"... Early receivers did not have an OTA module and it was a separate thing. Now it's integrated, so that's pretty cool.) It was neat at the store, flipping back and fort between the HD and SD broadcasts of a football game on CBS on adjacent channels. In my area, there are a bunch of local stations broadcasting in hidef including PBS. I'm hoping that my antenna picks at least some of them up well.

There is also HDNet, and HDNet movies. HDNet was showing a hockey game while I was in the store, looked amazing in HD. I'll definitely watch a lot more hockey now. Just in time for this season, too!

There is Discovery HD Theatre, which is fun. And ESPN-HD.

Then there's HD pay-per-view options, and that's about all for now. Supposedly a few more are coming online this year, such as Skin..., er, Cinemax. The whole deal is listed here.