thanwu, it's not just you. It's because all the channels you mention that look good are 1920x1080. All Voom and some Dish as well as all DirecTV channels are 1280x1080. We like to call it HD-Lite. Just in the past month Dish started to down-rez and DirecTV has been doing for over a year. You check the facts at two places:

Dish Bitrates
DirecTV Bitrates
Satelliteguys.us

The last link has ALL the details you'll ever need on satellite. I’m not sure about other cable companies but in most areas Comcast transmits true HD. I noticed my HD go to crap Jan. of 2005 when DirecTV started their down-rezing. I’m still holding on to DirecTV until after March when Dish releases their new mpeg4 boxes and to see if they stop the down-rezing. With Dish's announcements at CES, the down-rezzed channels may not be back any time soon. BTW, I’m not here to argue what anyones eyes see, sure it may look good to some, mainly because you haven’t seen true HD or your set doesn’t support true HD rez.