Lightweight inexpensive laptops?

I'm new to laptops, so please forgive my dumb questions.
1. Why are wide screens so popular? They add weight and bulk. Good for movies, but we use the TV for that.
2. My student daughter and my teacher wife don't want heavy laptops. It seems laptops under $800 are heavy, and usually widescreen. Can anyone recommend a 5 pound laptop for under $800? One non-widescreen with S-video out (for teacher use of TV monitor in classroom), and the other whatever is best portability and value for student - no gaming (widescreen would be OK but not preferred).
3. Are laptop displays like LCD monitors -- you should keep them at their default resolution? People start needing reading glasses in their late 40s, so we don't want high resolutions with small print. Is there an easy workaround to use a widescreen's full width with larger font/images other than resetting every document's magnification? This is one reason we think a non-widescreen would be better -- bigger image per screen size. If I'm wrong, please explain.
Thanks very much for your help!