hexkid: I believe you could always by default close a tab by middle clicking on the tab - I never done that, which is why it was a pain when that right X was missing to close a tab.
What I love about Firefox - like in your screenshot, you have a lot of "empty" space next to the "File-Edit-View-....Help" menu - I've moved the back,forward,reload,...Home buttons up to the left of the menu, then moved up the address bar to the right of "help" (removed the search since I just go to google if I need to search) - and now everything is in one line, leaving even more room for the web page to display. (My screenshot - http://coan.net/screen.gif )