If I understand your question right I don't think there is one good answer. It would be based on what you have your screen resolution set to.
I'm a 1024x768 kind of guy. That gives me quite a bit of screen real estate meaning less scrolling. Much more than say 800x600 which would require more scrolling. Then you have some people that can stand 1600x1200. That is a lot of screen real estate there.