When OS X 10.5.0 (Leopard) changed the way that folders are represented in the Dock, I lost a handy start menu made by dragging the Applications folder to the end of the dock.
Under 10.6 and later, you must Control-Click to see the AppMenuBoy dock menu.
AppMenuBoy is a small Cocoa application that creates a hierarchical menu, in the dock, and when it is the frontmost app, in the menu bar, of your apps. It only shows apps. If a folder has a single app, it hoists the app up, so no subfolders of exactly one app.
Version 1.0.4 adds:
Version 1.0.7 adds: