Cosmetic Customizations to Firefox???

Tweet

I would like to do something like what Lifehacker is having now. Can you guys show off and at the same time give me some new ideas as to customizing Firefox? This would mostly be cosmetically but normally even cosmetic changes cannot be made without the use of some extensions and scripts.:) I've attached an screenshot of my current Firefox. Hope to get some comments and/or ideas from you people!!!!:)