I started using Firefox 29 beta. This version of the browser has a new UI called Australis with curvy tabs that look somewhat like the Chrome browser. I felt the new tab look was too heavy and over-dominating so out it goes! I updated the Minimalist White theme to support Firefox 29 beta. Install it at user styles.
I use the Monokai Bright Sublime 3 theme mostly for editing HTML. It bothered me the bracket highlighting for HTML was so hard to see. So I edited the theme so HTML tags light up with an electric blue underline effect. Download the theme. On my system I located the theme file in C:\Users\mark\AppData\Roaming\Sublime Text 3\Packages\User\Color Scheme – Default. In the Sublime menu you can then set the theme from the Preferences menu > Color
I have been experimenting with giving Firefox a flat design look with inspiration from Safari and iOS 7. I wanted to get rid of all the borders, gradient backgrounds, and boxy look. You will need to install Stylist extension and then install the style. I also suggest updating the scrollbar look with Mac OSX Scrollbars for Firefox.