Widescreen all the way. It feels better looking at it. I think humans' eyes are developed for looking side to side more than up/down.

Plus, movies are widescreen now.
And all games coming out support widescreen now.
Only thing 4:3 is better for is reading.

Higher resolution the better.
I got a 1680X1050 on my laptop.
I just bought a 1920X1200 for a desktop.