I am fortunate enough to have 3 Flat Screens. Two 25" with one 21" on the right.
Because of the type of work we do, I typically have 2 CADs running with a Text Based prg on the 21". Though, there are times that I have several, (6 or more), CAD running on all 3 screens, two CAD per screen.
I am very fortunate in that my boss gives me pretty much what ever I need to improve my speed.
craigr