One aspect of web design that presents a challenge for designers is screen size. In print design, your canvas is fixed - once the size is set it wont change. On the web, not only do you have multiple screen sizes, but the user can also resize his browser window at any time.
The safest approach is to design for all monitors. However, many users have 14" monitors. The solution seems simple. Design your pages to fit on a 14" monitor.
While this solution does take everyone into consideration, it leaves those with high resolution screens with the short end of the stick. Fortunately there is a solution that cures all in my opinion. Its called fullscreen flash and it is becoming the new standard for presenting interactive content on the web.
Notice that the content will fit whatever space is available and on resize the content streches and/or repositions itself to the available space.