Classic Shell @ SourceforgeClassic Shell is a collection of features that were available in older versions of Windows but are removed from Vista and Windows 7. It has a classic start menu for Windows 7, it adds a toolbar for Windows Explorer and supports a variety of smaller features.
More InformationVery nifty. If you ever had any problems with Windows Vista or 7 having removed some useful features of the interface, this probably fixes that for you.
Adds the classic start menu completely seamlessly to the Windows 7 interface, allowing customization to keep the best of both worlds (the search bar from Win7, customizeable menu groups from Windows XP, and a cascading "All Programs" menu instead of the scrollable monstrosity of Win7, ability to adjust menu icon sizes...)

So far, I'm loving it. The search bar in classic menu doesn't work quite identical to the proper windows start menu - but, you can use both! By default, clicking the start menu or windows key opens classic menu after installation, while shift-clicking it opens Windows 7 start menu.
I've set it to open Win7 start menu with Windows key, and classic menu with mouse click; this way I can use the full extent of the search bar when I can't bother reaching for the mouse, but can actually use menus that make sense if I want to.