Do all channels look bad? Take a look at the premium channels or the PPV channels during the 5 minute previews at the beginning of a movie. Those channels have the least compression and should always look good unless something is wrong with your setup.
Just out of curiosity (not that it really matters to me, since I don't have or plan to get HD), but why don't they also put Bravo-HD on 274 and TND-HD on 246? The network HD channels could be remapped to the 390's as well.
Connect the better tv via composite cables or s-video and the other by coax. I have an RCA430 receiver and have a DVD Recorded connected to it via s-video and a coax running directly to the tv so I can watch tv without turning on the dvdr. Be better if the receiver had two sets of a/v outputs...
Having sampled XM on their website and hearing how annoying some of the DJs/announcers are, I'd much rather have Music Choice. The announcers are as bad if not worse than the ads. At least radio ads are entertaining sometimes. :)