Here at work, I have dual screens running for software development works. Left screen (Dell 2005FPW) has the IDE, the right screen (19" Samsung CRT) is used for document reading, internet browsing, mail, bugtracking software, etc. etc. I could easily use a 3rd screen here. 1680x1050 and 1400x1050.
At home I have twin identical 20" SPEA CRTs because I can

and because the right one doubles as a TV while I'm doing the usual home office stuff on the left one - or while I relax on the sofa in the study. 1280x960 on both of them.
Graphics card here at work is an AOpen FX5200, at home it's a Radeon 9550SE/VIVO.