DisplayFusion is a free (as in beer) application for managing multiple monitors. It has features for setting different backgrounds per monitor, or setting a background that spans all monitors. It also has some hotkey settings for moving and tiling windows between monitors (I really like the Win+S shortcut to center the active window and size it to 75% of the active monitor’s size). While I miss the Windows taskbar extensions that Ultramon has, DisplayFusion beats Ultramon on price (Ultramon is priced very reasonably anyway, but free is hard to top :-)), works well and is quite polished.