I just came across this nice little mock-up of an application launcher for Ubuntu Linux created by Brad Jensen. It incorporates the look of Mac OS X Leopard's dock, and it adds a system navigator and search interface which pops up when you click on the system icon.

The difference between Leopard and this is Leopard's dock is for launching apps from the icons directly on the dock, this has menus in it for launching apps and keeping things sorted, and then the icons on the dock are for apps that are running. It's like all of your panels in one simple to use, good looking dock that can be set to auto-hide. and have effects for fun if one wants them.

So, the bubble/dock combo replaces the standard Ubuntu apps panels. Neat!

More here