When Firefox 2 came out and had a close button on every tab I thought it would be great. Convenient and easy to find. Then I started closing tabs accidentally. Sure, they can be re-opened using “History” -> “Recently Close Tabs” but that doesn’t always get back the data when I’m using a web based app.
So it’s back to the old style with the close button and the end of the tab strip. This has the added bonus of giving more space for the tab titles.
To do this simply go to the url about:config and filter for browser.tabs.closeButtons and change it’s value to 3. Other options are 0 – display on active tab only, 1 – default behavior, 2 – no close buttons.