UltraMon (64-bit version)
Multiple monitor setups aren't easy to manage. It takes tools like UltraMon (and close competitor Actual Multiple Monitors) to give you more control over that expanded desktop space by adding new user interface elements to the desktop, buttons to the title bars of Explorer, and program windows that let users quickly switch an app's window to another desktop.
Like AMM, UltraMon's principal feature is to extend the Windows task bar to all monitors. (By default, Windows displays the task bar only in the primary display.) UltraMon's extended task bar shows only the applications or windows that are within a particular display's desktop space. For example, if you have four programs running, two on each display, then each respective display's task bar will only show the programs running on that particular display. As a long-time user of "old fashioned" multiple displays, this took some getting used to. Occasionally, I'd forget that a program was already running (minimized) in the secondary display, and didn't look at that display's task bar before attempting to launch another instance of the same app.
At default settings, UltraMon's task bar extension gives each display its own task bar, each of which shows only the applications with open windows in the respective display. By contrast, Actual Tools' program makes a complete duplicate of the entire task bar, including the System Tray and Start button, on all displays, as its initial setup. I found the slightly less cluttered task bar more appealing, though some might welcome the consistency in having a mirror-image task bar appear at the bottom all displays.
Both programs add a button to the title bar of app or Explorer windows, which lets you pop that window laterally, from one display to the other. If your displays use different native desktop resolutions, UltraMon's got you covered. The programs can also dynamically resize window-moved-to-another-display so it appears to take proportionally-sized desktop real estate on its destination display. One seemingly extraneous feature: Both programs can tweak your screensaver settings so you can run a single screensaver across several displays or different screensavers on each display simultaneously. Entertaining, but not especially practical.
UltraMon adds a button to the title bar which maximizes the window or application across both displays, so it fills the entire space of all displays. This could save a lot of scrolling in spreadsheets, image editing, and other applications and documents that run wide.
Both programs let you assign custom hotkeys to various program features, such as the ability to toggle the position of an application or window from one monitor to another. UltraMon's custom hotkeys offer a lot more options than those provided by Actual Multiple Monitors--25 possible hotkey combinations, compared to AMMs' 10 options--including the ability to launch apps or scripts with a keyboard shortcut. Among the additional hotkey possibilities, UltraMon offers this tantalizing option: Run application or script. The ability to generate a keystroke shortcut for any arbitrary command-line operation demonstrates that UltraMon has earned its geek cred. After writing the scripts, I typed that entire sentence in nine keypresses.
UltraMon offers powerful tools for users of multiple monitors to get more out of that kind of configuration. The powerful keyboard shortcut feature makes it appealing to the power user. Although it costs a full ten-spot more than the competition, UltraMon is definitely worth a try if you want more out of your multiple monitor setup.
Note: This software comes in 32-bit and 64-bit versions. This is the 64-bit version. If your PC is running a supported 32-bit OS, please download the 32-bit version instead.