1024x768 is the standard resolution for a 17" monitor

you should be running 1280x1024 if you've got a 19" monitor

Widescreen monitors are a little different.

I do a lot of we development myself and I always design the pages to work with 1024x768 in full screen, depending on the site I'll get it to work with 800x600 screens as well.

Personally I use 19" screens but I never maximize my browser so my effective "screen size" is always smaller than my actual screen.