HD is terrific but a lot of people have an impression that all you need is the TV and you're set to go.
Many cable companies rent an HD converter box...if not, you're going to have to shell out for a satellite dish set-up. And either way, you're not going to get a ton of HD content. Perhaps 12 channels at the most.
Vegasisdead, what's the model number of your TV? $3k is awfully expensive for a 30" set. Gateway had a deal a few months back for a 40" Panasonic plasma EDTV at $2500. IMO, that's the best deal ever on a wall unit.