As Mac Allock stated, most affordable widescreen monitors support 1440x900 resolution. thus presenting more things on the left-to-right direction as in cinema displays than on the up-down one, compared to 1280x1024 "TV type" ones

there maybe a concern to you if you are using aplications that tend to grow in the up-down direction.

Example: you are using a soft synths and a VST rack as Forte...
the more synths you stack, the more the stack grows vertically. It may be a poor paradigm but sometimes if you stack 4 of them, they may fit in the 1024 vertical, 4:3 monitor, but in the 900 vertical you may have to scroll up down to get to the last one.

Don't know if I made myself understood here, someone else give a more useful paradigm?