Dual Screens?

[Ice Rich]

Hi all,

I have seen a lot of pics of peoples set-ups using dual monitors.
I can see it of being of use but what do most people use it for? I.e work on one whilst playing a game on another?

Also, I take it you obviously need a dual output video card? Is there much of a performance hit using 2? Also, is it wast to setup?

Thanks