Just about every game developer should have dual monitors, if not triple. Its not really to "impress" people -- Trust me I'd rather have had saved my money on buying two more monitors, and used it on other things, but the workflow practically requires it and is much easier this way.
I don't have any pictures of my set up, but it's basically the same as some of the above shown setups. Much like Lodle's setup. My main monitor is what I do all my modeling, texturing, animating, etc. on. The second (right side) is mainly for references. Except on my 3rd monitor (left side) I'm running a different PC, so that I can be running a game build, in this case GoldenEye: Source, while I am working on things at the same time. -- All are 23" Dell LCD's.
This was very beneficial when I was freelancing work for Crytek, working with the CryEngine 2 sandbox running live on my 3rd monitor.