Re: 4:3 issues and burn in.
2 points, both of which have been touched on above:
1.) Watching 4:3 in its original aspect ratio does not pose a serious risk of "burn in" after a reasonable period of break in has occured (a month or so). The main concern, really, is reverse burn-in. That is, the pixels in the center of the screen will lose their brilliance faster than those on the edge of the screen over time. First, this is a bit of an absurd scenario and would require the watching of tons of 4:3 content and close to no widescreen material. This, of course, begs the question of why an HDTV is necessary. If all you are going ot be doing is watching sydicated re-runs or 4:3 encoded DVDs, then you won't gain much advatange (aside from the slim profile) of an HDTV. Second, considering that plasmas fade to about half their brightness in about 10 years (source: ?), perceiving a noticeable decrease in mid-screen brightness b/c of watching 4:3 material is not a real concern (at least of mine).
2.) There are a number of very well done "stretch" modes on HDTV's these days that combine side to side stretching, vertical zooming and parabolic lens shifting near the screen edges together to create a very convincing widescreen image from 4:3 material, with minimal loss of on-screen information and very subtle vertical "smooshing". I watch most of my 4:3 material this way (which includes Simpsons re-runs, cooking shows, and other low-def material on cable). While I guess I am not a purest, this is a very good compromise, in my mind, for getting a picture to fill the screen (as preferred by my wife as well).
