I used to have a really hacky AppleScript to do the same thing in OS X. The crappy part was that launching the whole AppleScript runtime was really slow, but that was the only API I could find with getting that information from the Finder.
You can also drag any file or folder onto your terminal, which will paste the absolute filepath at your cursor point.
Yeah, but I rarely use the mouse when using either a file browser or the terminal, so switching to it is less convenient than a short terminal command.