In recent versions of Ubuntu and particularly the upcoming 14.04LTS, I find that I prefer to not use tabs in Firefox, but rather use the app spread. So that's what I do. However, I haven't found a way to remove the tab bar from Firefox and it seems kind of pointless for every one-page window to have a tab bar containing only one tab. Sometimes, it also fools me into using the new-tab button from old habit, so it would really be quite useful to be able to remove that bar altogether.