Just found out this plugin from Firefox plugin gallery. Am really impressed. This is what i was looking for. No need to install themes. This is all in one. This is called “Personas“. Click on this to install.
Personas are lightweight, easy-to-install and easy-to-change “skins” for your Firefox web browser.
To access the gallery here is the link : http://www.getpersonas.com/gallery/All/Popular
If Personas in already installed then just mouse hover over the gallery image to get a real preview of the theme. This is so dynamic.. I am loving it