1000*500 ? (Score 1)

From what I've gathered from lurking behind people's back in public libraries and cybercafes, you're safe when assuming a 1024*768 screen. It seems that Windows users who don't know how to use a computer know at least "Close box" and "Maximize". Therefore, once you remove task bar / menu bar / Dock / toolbars, you have more than 500 pixels in height, and a good thousand pixels in width.