comcast's site in denver is pretty out of date.
My Network TV
Discovery HD Theatre
ESPN 2 HD
PPV HD On Demand movies.
InHD carries any HD events from our regional sports net (altitude). They also carried the OLN HD NHL games from last season.
some markets still have InHD2, but that is being phased out system wide, i believe. I know other markets also have Universal HD and MHD (mtv's HD music channel) but i think that tops out the list of channels that are carried in HD by comcast nationwide.