If your video card can support the higher resolution you will end up with more desktop space. You could have two browser pages side by side, for example. Or have a browser at it's normal resolution with an email open to the side, for example.

Definitely go widescreen if it's an option. I use dual monitors at work and it's the same effect. I now have a 2407 for home which makes browsing and everything much more friendly rather than having stacked windows. Games are all messed up right now but that's neither here nor there....

hi legality,
I would forget 19" - it is only the same resolution as a 17" anyway. So the question is 20" 4:3 or widescreen. The 20" 4:3 actually has more screen real estate:

20" 4:3 is 1600 x 1200 = 1,920,000px
20" 16:10 is 1680 x 1050 = 1,764,000px

20" 16:10 is like a horizontally stretched 17". I have a 2007WFP and have apps like browser open in an approximately square window, which leaves space beside for a small DTV window and IM or Yahoo widgets. Other apps work really well fullscreen. While this is an improvement on my previous 17" CRT, I now find myself wanting more height. Next monitor might have to be a 24" widescreen :)

This comparison might help:
http://tvcalculator.com/index.html?db2808fb4273e3c2063d4f20c006495f

Thanks all......I don't think I need anything larger that a 20", but I will seriously consider the widescreen.