Using the 30" as a TV
Seriously, I think that many people are overestimating the ability of a computer monitor to substitute for a TV. A good rule of thumb is that seating distance for video should be about three to six screen widths away from the screen. If you go through the math, that is around 2-4 feet seating distance for a 30" 16:9 screen. Of course, your personal home theater setup may vary.
Furthermore, putting a TV screen on the wall will increase the size needed for the same viewing experience. Having a conventional or rear projection TV puts the screen surface about 18" in front of the wall in a typical home setup. By mounting a plasma or LCD screen directly on the wall, the viewing distance is increased, requiring a larger screen for the same relative viewing experience. Again, if you work through the math, this works out to be about a 10" increase in the screen diagonal -- in other words, if you have a 50" RPTV, you'll need a 60" plasma on the wall to get the same viewing angle. A 30" screen on the wall is more like a 21-24" conventional TV.
Besides, a quick trip to Best Buy or Circuit City will show (to me at least), that the minimum usable size for a conventional 16:9 TV for typical home use would be a 34" model. The screen height for this screen is along the lines of a 27" 4:3 TV. A wall mounted screen of the same size would have to be at least 42" for the same viewing angle coverage.
It will be nice if we can get a 30" LCD screen. I just wouldn't expect it to be an adequate substitute for a TV. When a wall mountable 42" HDTV computer monitor becomes available, then we can talk.