How big is too big?

If you're not buying HDTV, audition the TVs from your expected viewing distance as Perfectimage stated. Buy the biggest screen where you can NOT see the horizontal lines. From 10-12 feet away you'll likely end up with a screen size 50-60 inches (I use 50 inch from 11 feet). If you're going HDTV, then the audition is that much more important because it will really be a comfort factor vs. performance. Hope this helps.

For a rear projection tv the ideal seating distance would be 5x the viewable screen height. For example if you own a 50in RPTV and the viewable screen height is 30in, than your ideal seating distance would be 5x30 or 150in or 12ft - 6in. After this advice read Sean's post.

As many have pointed out it's the viewing distance that matters, but it also has to be coupled with projected resolution. When I watch a movie I don't want to see scan lines. If you project too large and you are too close you will see those lines. Other than that--the bigger the better in my opinion. Does anyone think IMAX screens are too big for the theater? SGTH did an article on this (distance vs resolution) quite a long time ago, it might be possible to find it in the archives. Just as a point of reference I'm using a 100 inch screen, seated 15 feet away, native resolution is 800x600 (CRT driven with Faroudja DVP220). Hope this helps.

Thanks for all of the help I just got a 100in front projection screen, and I think I might have been able to fit a 120in. Very overwhelming just what I wanted heh heh heh.