1. Prettify the Firefox widgets in Ubuntu
Make the widgets (radio buttons, check boxes & text fields etc.) in Firefox inherit their styles directly from the theme you are using in Ubuntu.
2. Reduce your Linux memory footprint
A lack of physical memory can severely hamper Linux performance. Learn how to accurately measure the amount of memory your Linux system uses. The article also gives practical advice on reducing your memory requirements using an Ubuntu system as an example.
3. 20 must have Firefox extensions
The best 20 extensions for Firefox listed by Computer World. Good place to find out about new and useful Firefox extensions.