All the space is just in that new and horrible default theme they are using. Try going through and picking a different theme where those icons are better placed, and will be prettier to boot.

http://www.texturizer.net/firefox/themes/

Thanks for the tip. That makes sense. Unfortunately, that site doesn't seem to be working. When I loaded it, it said there were 0 themes available. Is anyone else getting that? Are there any other sites for themes?