Firefox

This is my firefox window... As you can see, two app tabs save space on the tab bar, and I have greasemonkey scripts for notifications for each. I now use the Hide Caption add-on, which removes the space-hogging titlebar. To center the URL bar, I just added the back/forward buttons, though I don't use them much. I'm using a minimal but pretty theme called rein. This has made my Firefox browser slimmer than my Chrome browser.

Done