I use a relatively cheap 32" LG LCD TV as a third screen. I put the PT video window on the third screen (And I find it really lame that there are always big borders around the window and it isn't true full-screen like any media player can do. Shame on you Avid).
Many of the places I work have these kind of screens: JVC Professional Features page
(Connected to Mojo's or V10's or whatever either directly connected to the PT rig or through a Media Composer rig running as a satellite).
Alistair Johnston - TV & Film Post, Mastering, Sound Design
"The first principle is that you must not fool yourself -- and you are the easiest person to fool" -- Richard P. Feynman
"There's a sucker born every minute" -- P.T. Barnum