I like having two monitors rather than one super large display. It's easy to maximize the AutoCAD graphics window on one of the displays and use the other for a variety of options including AutoCAD panels (properties, layers,...), help files, email, reference documents, etc. keeping your main CAD area clean and unobstructed. Of course you can always stretch the AutoCAD window to fill the two monitors (something I rarely want to do). You can get a couple of 20" Dell monitors for less than $200 USD each.