FYI the $99 "normal" DVR can be used to receive HD signals by downloading a software update that makes it exactly the same as the $199 HD-DVR. The 800 number won't tell you this, of course. It is pretty new, though. Found out from an installer a couple of weeks ago.. AFTER we bought an HD-DVR (lease, really... to buy them costs over $500) and he came to install it. So he updated our old regular DVR, moved it to the bedroom, and now we have two HD receivers.
I do agree with the PP - once you go DVR you will never want to go back. DVR is by far greater than sliced bread.