In my opinion, one of the biggest drawbacks of OS X is the lack of a working global hotkey system. I usually have several applications up, some of them hidden, some of them minimized to the dock. I want a quick way to be able to bring all the windows of a given application to the foreground with a single key sequence. None of the solutions on macosxhints seemed to work 100% correctly. Some didn't work at all (e.g., using AppleScript plus hotkeys). Others required lengthy configuration screens. One, when improperly configured, caused OS X to launch every single application in the /Applications folder (ouch)! And worst of all, most of them wanted to charge money for a service that really should be a free part of an OS; even Microsoft Windows has it for free.
Then I found FreeHotKeys. This application is free, not "try-before-you-buy." And best of all, it requires no configuration at all. Just run it. Then, to bring up an application, type option-command + the first letter of the application. Want Mozilla? option-command-M. Want X11? option-command-X. Now, If you are skeptical and saying to yourself, "Gee, that doesn't work for me, I want to be able to change the hotkeys," my advice to you is to try it anyway, because that is exactly the same thing I thought at the beginning. Now I'm addicted to the option-command system.
Get it here: http://batista.org/freehotkeys.html
By the way, you can also assign function keys to AppleScripts and this time it works. Also, this is an application switcher, not launcher. You will have to launch applications manually for yourself---which is fine by me because I usually only do it once per day.
Another note: if your application's windows are minimized (located beside the trash on the Dock) rather than hidden (completely out of view), then no application switcher I've found will bring them to the foreground. As far as I know, FreeHotKeys and others bring up only "Hidden" windows, not "Minimized" ones.
Mac OS X Hints