Web Monitor Resolution Debate

Although a screen resolution of 1024 x 768 is predominant in the US, Europe, and Japan, in some areas, such as South East Asia, smaller screen sizes such as 800 x 600 may still be common. Flexible design approaches help significantly in addressing such differences these days. On the other hand, there are also a lot of other devices (PDAs, cellphones,...) with much more restrictive screens. Although not all Web pages may need to work on cellphones, try to design with as few limitations as possible.
Straight From From World Wide Web Consortium