I'm coming to you now from a desktop with three displays: A 24" iMac display, 19" LCD external monitor, and 12" internal PowerBook display. It's ridiculous -- my desk looks like it belongs to the Biggest Nerd In The Universe.
Everything's all networked together. I can move my mouse cursor from the 24" iMac display to the 19" display attached to the PowerBook to the 12" internal PowerBook display. I can share files between the two computers, and even copy information into the clipboard of one computer and paste it into an application running on the other.
How do I work this magic? I connect the PowerBook displays and the iMac display using a dandy open source utility called Synergy. Synergy lets you share keyboards, mouse, and clipboards between multiple computers running different operating systems with separate displays. It works on Windows, Macs, and Linux.
I've been giving Synergy a good solid workout since Monday morning, and it's held up like a trooper, with only two problems, both minor:
Usually, when the PowerBook goes to sleep, it wakes up when I move the mouse cursor over to it. But sometimes it doesn't. I have to touch a key on the PowerBook's internal keyboard. Darn it, I didn't go to college to do that kind of heavy manual labor!
I use TextExpander to automate typing out long phrases. I have it installed on both the iMac and the PowerBook. When I'm running Synergy, TextExpander doesn't work on the PowerBook -- it tries, unsuccessfully, to invoke TextExpander on the iMac. I think I may be able to fiddle with the settings of TextExpander to fix that problem.
The other thing I had to do to run my three-display setup is set up the PowerBook to use an external display. It's pretty easy:
First, plug in your external display, of course.
Click the apple icon in the top left of the main display. Select Preferences, then Displays.
Look for a checkbox that says "Mirror Displays." If you want your displays to show different information, make sure that box is unchecked.
You'll see two blue squares, representing your two displays. You can move them around to set the virtual arrangement of your displays. You'll probably want the virtual arrangement to match the real-life, physical arrangement of displays on your desktop.
One other thing you'll want to do: You'll see a white, horizontal strip at the top of one of the blue squares in the "arrangement" window. The white strip is the symbol for your menu bar. You'll want to be sure the menu bar is on whichever display you're using as your main display. You can do that by dragging the white strip from one box to another.
Although I have three displays on my desktop, I'm really only using two of them: The 24" built-in iMac display, and the 19" external PowerBook display. The 12" display is too small and far away to be useful -- for now. I'm trying to think of what to put in it, something I want to be able to keep in the corner of my eye all day.
Right now, I'm working away in a text editor in the center of my big 24" display, with instant messaging clients sitting in the edges. On the 19" monitor, I have my corporate e-mail client, Lotus Notes, where I can keep an eye out for incoming important messages. And I have my custom NetVibes home page on the little 12" PowerBook internal monitor, with InformationWeek's own RSS feed in a place of honor, front-and-center.
(Of course, all of these things running at once might not be the best idea, productivity-wise. Even under the best circumstances, I have an unfortunate tendency to be distracted by bright shiny objects.)
Do you use two or more monitors on your desktop? How many do you use and how do you use them?