I have been using 2 Samsung 19" monitors, I am upgrading my photo system, so here's a question is it better to use two 19" or 20" sqaure monitors or one big theater style? I want ample room to be able to open PSCS with Bridge and Lightroom and my images. Those who have tired both I would be very happy to hear from.
One benefit of 2 monitors rather 1 big one is you can maximize separate applications on each screen, which is handy when juggling multiple windows and applications. For example, I tend to have Bridge maximized on 1 screen, PS maximized on the other and then I keep things like email or IE smaller and movable.
I use two monitors. On two computers, controlled by a single keyboard and mouse.
Since I went a 24 inch iMac and a G5 with a 23 inch ACD, working on images using one monitor is quite nice. There is much more real estate on the wide screens, and the layout of LR fits perfectly. Most images I shoot are used 11x14 or smaller, so it's like working on actual sized finished product without the expense of a second monitor. I did use 2 laCie 19" in the past on one G4 which helped, but one large wide screen works for me now.
I split the work load across the two machines. All photo editing delegated to one computer, most other tasks on the other. Multi-tasking is much easier on current machines, but even quicker on seperate units.
I use a nice little open source utility called synergy to control both computers ... works great.
If you have two computers and a KVM then two monitors work better. If you have one computer a single large 16:9 aspect ratio monitor works better than two.