What kind of stuff is there to tweak on a TV?
On a regular tube television, not a lot. On a projection TV, plenty.
Stay away from the 16:9 TVs because you'll always have black on the sides, even with widescreen movies
I know you just made that up, but a discussion of this is important if HDTV is going to be part of your decision process.
Movies/HTDV and regular television shows are different shapes. The black bars are going to be a fact of life as long as there's more than one format.
If you have a square television, then widescreen movies and widescreen HDTV broadcasts will have black bars. If you hav a widescreen television, then square movies and television shows will have black bars. You can't win. You're going to get bars one way or the other.
Even among widescreen movies, there are different shapes. The most common are 16:9 and 2.35:1. So you sometimes even get small black bars when watching the 2.35:1 movies on a 16:9 screen.
Something to note: The Mits widescreen televisions have some interesting stretch and zoom modes which allow you to watch differently-shaped material that still allows it to fit the screen. Personally, I don't use them. I prefer to watch the image in its correct shape. It's nice when that "correct shape" happens to fill my 16:9 screen, but it's not a problem, really.
See, the RPTVs are great because their screens are so big. When I watch a 4:3 television show on my wide screen, it's still bigger than a tube TV and looks fine even with the side bars. On the other hand, watching a widescreen movie shrunk down to tube-TV size is painful. This is why the widescreen RPTVs are selling so well, because they make the real movie-watching experience possible without sacrificing the regular TV experience.
Avoid HDTV if 99% of your viewing will be normal NTSC
This is only true if your only viewing will be from a little-dish satellite system. Those are so heavily data-compressed that when you enlarge them to big-screen HDTV size, the data compression artifacts become painfully obviuous. If you watch a lot of broadcast television or have C-band satellite, then an HDTV monitor will allow you to watch regular television just fine while also giving you a great experience for DVDs and HDTV (with proper receiver).
The only problem is that most people can only get HDTV through a little-dish satellite system these days. When you buy one of those, the HDTV part looks great, but you will be underwhelmed by the NTSC part in comparison.