You can enable the display of the path to each Finder window as that window's title by typing the two following commands in the terminal:
$ defaults write com.apple.finder _FXShowPosixPathInTitle -bool YES
$ killall Finder
While you can't edit or copy the path, this feature can still be useful for power users. It is similar to the Path Bar in Leopard's Finder, but it shows the path in a more compact way, and in a format that power users are used to.
[robg adds: This can get somewhat ugly when you drill way down into the file system, but it definitely works.]

