In all of my research unforutniately Comcast has the most HD channels to choose form.
I have been looking to dump Comcrap but I just can't now that I've gone HD.
And for the record I've been watching HD for about a year now and yea its the snitz...

Comcast boradcasts channels INHD 1 and 2 and even though they are a little slow to update their programing content these 2 channels are broadcast in the best HD signal Comcast can send and you can see it... Realy amazing stuff...
They run a lot of stuff that was shot in IMAX and all I can say is wow.
They are also broadcasting our Mariners in HD like they did last year and if you had watched last years games you can see that they are playing with the depth of field on these cameras. Last year you could plainly see the crowd. I mean so clear that you could see what a guy was eating and stuff.... This year I noticed that in certian shots the crowd is being blured out especially on the close ups which quite frankly is too close... I really don't need to see the hanger in the pitcher or batters nose... LOL
Definately a big difference in pic quality....

Oh a word of warnig to perspective HD buyers....
Regular cable signals look like crap on all HD sets.
In all of the sets I demo'ed before I got mine the regular 480 sig looked realy crappy. If you are not going to get an HD reciever or OTA antenna with a box that can pump the HD sigs to your new HD then wait.
You will not be happy watching regular TV on a 1080i HDTV.
There are certian models that look better with the regular cable signal, but none of them, even the highend Mits and Pioneers, looks as good as a regular old 480 4:3 set when viewing the regular cable signal, so if basic cable is what your going to watch then I would wait.

DVDs are great too but the DVD player does make a difference along with componet cables.
I had an older Tosh DVD player that was progressive scan and I replaced it with the Panasonic XP30, before they discontinued them, the difference between the two pics on my HDTV is quite noticeable.

Just as this forum is here for us comp/tech geeks there are lots of forums and info out there on HDTV's and DVD players.

I found the hometheaterspot.com was a great source of info and they have a lot of techs that frequent that site, but thats only one of many out there...

Hope this helps someone good luck,
"g"