If you want new Microsoft-branded skins, styles, or themes, and are currently a MSDN member, you are in luck. You can install Windows XP Media Center Edition 2005, and enjoy the themes and more.

If you are not a MSDN member, or do not have that edition of the DVD, buying the Plus! Power-pack for Microsoft Windows XP will give you many added features.

For more features on Windows XP that do not need you to directly modify the registry:

Download Windows XP PowerToys. These PowerToys will allow you to quickly and easily modify Windows XP, and its' features. Windows XP was not meant to be optimized... that is what I love the PowerToys for!

You can also modify many other aspects of Windows XP through the control panel, or by using third-party applications.

One thing I go by:

I NEVER trust other people's modifications on MY computerS. I have multiple of them, and if I mod all of them, and something happens, I am risking my whole network. I ALWAYS backup modified programs because I have been ****ed in the past.