I disagree with Ed and others who say it's not worth it going to a flat panel.
Here are the facts. If you have a decent scalar circuit in the flat panel HDTV, the picture it makes will look at least as good as it was on your SDTV at the same size and viewed from the same distance. If it looks worse than it did on your SDTV, then you bought a rather crappy HDTV.
Now there is a strong tendency to (1) buy the biggest flat panel TV we can afford which (2) winds up showing us a much larger picture than we ever saw before on our old analog sets and (3) because it's big and cheap it probably has a crappy scalar. I believe this is the true origin of all those naysayers above who say "Don't buy an HDTV until you can afford the HD service." Fooey. Many went for the size, and not the guts, of an HDTV.
Indeed, if you blow up a standard def picture to enormous proportions and put your nose on the picture, you're going to see the flaws and they are not pretty. That's not what the OP says he's going to do. On the HDTV plus side, even keeping SD satellite service for a few months, he will be able to watch OTA and clear-QAM and blue-ray and media player HD pictures on his HDTV at no extra charge. DVD videos, though SD, look pretty darn good too.
Edit: diagonal measure of SDTV X 1.24 = diagnoal measure of widescreen HDTV with equivalent SD picture size (ignoring overscan, rounded edges, front panel bezel lapping, etc.)