Is there a keyboard shortcut to close all applications in Mac OS X Snow Leopard?
There isn’t a built-in keyboard shortcut that does that and only that, no. Command-Option-Eject will quit all applications and restart your Mac, and you’ll be prompted to save whatever documents you have open in each application before it closes. And Command-Option-Control-Eject will quit all your applications and shut down your computer (with the same prompts to save open documents). So if you’re looking for the quickest way to quit all your apps before shutting down, that Command-Option-Control-Eject shortcut is all you need.
Quit 'em all with Automator's help.
But if you just want to quit all your applications but not restart or shut down your Mac, you need to turn to our old buddy Automator. First, fire up Automator, and in the “Choose a template for your workflow” dialog, select Application. In the Library list in the sidebar, select Utilities, and then in the resulting Actions list, select Quit All Applications and drag it to the workflow area to the right. That’s basically it; it’s a one-Action workflow. There’s a checkbox in the Action labeled “Ask to save changes,” and we recommend you use that. You can also exclude apps if you want certain ones to always stay open.
When you’re done, just press Command-S to save, give your application a name, and save it wherever you like: to the Desktop, to the Applications folder, wherever. Don’t forget you can stash it in the Dock or your Finder windows’ sidebar for easy access.