I watch a 34" widescreen tube from 5'. It usually seems big enough to be involving, but can seem a bit small when watching material with a very wide aspect ratio, because then as much as 1/3 of the screen may be black bars. SD material looks great on it, but I don't think I could go bigger (or closer) without seeing the pixels. I have considered a larger screen, but I don't have room to move back much. (Also, tubes still have the best picture of any screen technology, and mine is as big as tubes get.)