I forget which podcast this was, or who said it, but someone was complaining that their Star Trek DVDs on a HDTV looked "like soap operas" -- meaning that they looked like they were shot on video tape.  I just got a HDTV, and I encountered the same situation.  This is due to "dejuddering" -- the smoothing of the image.  Turns out you can smooth too much.  There is a fix for this.  Dig around in your TVs settings for the blur reduction area.  If you have a TV with different blur and dejuddering settings, turn your blur reduction to 10 and dejudderiung to 0.  If the two are linked, or you don't see a dejuddering setting, turn your blur reduction down.  Try 5 or below.  You may get more blur, but film-based media will look more film-like.