LittleFox, designed for optimal screen usage, leaving lots of room for browsing. Includes support for many extensions.
Install the About Home Themer extension to also theme the about:home page.
An extension to hide the caption of Firefox, displays Minimize, Maximize/Restore and Close buttons on the menubar/nav-bar, and includes "Tiny Menu" function. This extension also provides "Bookmarks" and "Histroys" buttons with popup menu.