The coolest thing is to put the desktop over two monitors, like shown above.
How to do that? My dell has a 256MB ATI Radeon X1300PRO. I selected "Start/Programs/Catalyst Control Center/Advanced/Catalyst Control Center Advanced" then the "Displays Manager". I set the Desktop area to be 2560x1024.
I know its annoying to have the middle of the virtual screen interuppted with the monitor edges, but two 19" flat panels are really cheap compared to a 38" screen.