UltraMon is a utility for multi-monitor systems, designed to increase productivity and unlock the full potential of multiple monitors.
They have a tour with great screencaps. For instance:
Next to the minimize, maximise, and close buttons in the upper left of your windows, Ultramon provides “Move to other monitor,” and “Maximize to desktop,” which stretches big apps across both monitors.
You can tell your application shortcuts to open your app windows on a specific monitor at a specific position each time.
If you have three monitors at work, but just two at home (the horror!), you can have profiles that quickly switch your laptop between the configurations.
Stretch your wallpaper across all your monitors. Create a bi-i-i-i-g picture. Like this one of the Paris skyline. That would be breathtaking. (Warning, that link goes to a JPG that 15,000 x 250. But it’s so worth it.)
For Windows only. $40. I’ll need this soon, because Joe is going to let me buy three monitors in a couple weeks.