If you have not lived under a rock for the last 6 years, you have definetely heard of Open-Shell. While it doesn't do circles around other programs, it is certainly impressive for a free program.
And, if you want a different-looking start menu, you can change its skin. If the built-in skins don't suit your needs, you can simply download more through the use of a search engine, and since I'm worried about your computer's security, I'd like to remind you that such skins usually come in .skin or .skin7 format.
While Open-Shell is commonly associated with customization of the start menu, the program also features basic taskbar customization features. It is free to download and its source code is freely available.