web browser, msn, winamp, AutoCAD... there's just loads of stuff on the go whilst I'm sailing the ocean blue. Got so used to 2 monitors that I couldn't go back to just one... same at work
Use 'dual view' on 6800 cards not 'clone' etc to span your desktop over the two so you can see both when game is running.. or something like that, also make sure that only your primary monitor has hardware acceleration- advanced settings single display mode.
Play with all those settings mmmmmmm