Don't think there's one specifically for Finder from any Application, but if you Cmd + Tab you can get to Finder pretty quick. If you use Quicksilver, you can probably set up a trigger that will open a Finder window from any Application.
Forgot about this post, thanks guys! Command + N opens Finder to the documents folder, and Command + up arrow opens it to my home folder. I just have to click outside of an open app for the keystrokes to work.
Are you sure about that? On my system it seems to be a system-wide shortcut to pause iTunes.
Never mind. That's odd, I have the Spotlight commands disabled and the input menu commands enabled, but command+option+space is supposed to be mapped to "next input source".
You're right, but that's exactly why it works. I don't think Apple's intention was for <Option-Command-SPACE> to be used as a keystroke to launch Finder, but it does the job just fine!
A number of people have noted that the keystroke can do other things as well. However, that's if you customize the default keystroke mappings.