Most cable and satellite programming looks lackluster on an HDTV set and it will still be a while before most shows are available at a reasonable cost in HDTV. HBO and Showtime, for example are way behind in even providing properly formatted movies in 16:9, much less in High Definition.
One way to get some of the extra value out of that set whose abilities are being under-utilized is to use it more often for DVD viewing.
While DVD's are not up to HDTV quality, they can match what is known as EDTV quality, if but only if they are viewed on an HD- or EDTV with a DVD player using progressive scan technology (i.e., DVD players made in the last couple of years)and if hooked up via three component video cables or one HDMI cable.
Some of the newer and better HDTV's may actually be able to implement the progressive scan themselves, although results vary. Some of the cheaper sets may improve by using a progressive scan-equipped DVD player. This is a bit like Dolby technology, where you need to have it at least in one place in the chain, but some components implement Dolby better perhaps than others.
Nevertheless, this visual improvement of DVD's to EDTV quality is possible only provided that one's DVD players are hooked up properly.
Check your cables--almost no one uses the 3 component RCA cables necessary to pass the signal--in total, it is necessary to use at least five RCA cables, including two for at least two channels of audio depending upon your audio set-up, to pass the EDTV signal to a HDTV set. Using S-video or three component cables will not suffice.