I usually "zoom" 4:3 programs to fill the whole screen. The images look a little squashed, but your brain adjusts to it.
However, I DO NOT zoom 2.35:1 programs to eliminate the black bars. If you do that, you\'re throwing away image information on the left and right sides of the screen. What\'s the point of using a widescreen TV, if you\'re going to willingly hide part of the frame? Seems like a stupid precaution to avoid burn-in.
I have a rear projection Toshiba 65H80 which is the old technology that IS suseptible to burn-in. I\'ve been running it for several years now, and I no burn-in whatsoever. You need to leave your set turned on 24x7 on a harmful image to induce burn in. I don\'t think any of us do that.