True Launch Bar - Today's Mod
But the quick launch toolbar is extremely simple, and definitely has limitations. If you want to supercharge your quick launch toolbar, consider running True Launch Bar, which is like quick launch on steroids.
Using True Launch Bar you can easily organize your quick launch icons into a menu system, using icons, text, or both. In fact, it uses the same directory structure as the quick launch bar, so upon installing it will immediately show you what you already had there. You can of course configure quick launch menus using a folder structure under your quick launch folder, but using True Launch bar the process is made much easier, and you're able to customize the look and feel of your menus in a way that Windows doesn't allow you to do by itself.
True Launch Bar is also extensible, and has a wide range of available plugins to allow you to show pertinent system information in your taskbar.
True Launch bar is shareware with a 30-day trial period. It costs US$19.90 to purchase.
[Update] As John points out in the comments, there's a free version called Free Launch Bar that I totally missed. It has many of the features described above, and is completely free. Thanks John!