Earlier this year I told you about QuickImage, a contextual menu plugin that adds all kinds of image related functionality to the default OS X contextual menus.
One of the other plugins by the same developer is CalculateSizeCM (bottom of page). It gives you the ability to quickly see how many files and folders are in a specific directory. I don’t need this feature very often, but when I do, this is a big help.
The page lists compatibility as “Jaguar, Panther” but I haven’t had any trouble running it under Tiger.