Widescreens have less viewing area. People lie and say that because the screen is wider, you get more viewing area. Because screens are actually measured diagonally, you don't. You'd get the most viewing area from a square screen, but those don't exist. 4x3 screens have more viewing area than 16:9 screens of the same size.
A 21" 4x3 screen has 218 square inches of viewing area, a 21" 16:9 widescreen has 211 square inches viewing area
Do the math yourself, you loose the equivelent of a 7x1" strip of space by going to wide screen with a 21" display. Pathagoreans theorum works, the @ key performs the square root function in Windows calculator.