Is it possible to get menus to be shown in always visible menu bars in 14.04, rather than in window title bars?
Yes, you should remove some packages. Use:
sudo apt-get remove --purge appmenu-gtk appmenu-gtk3 appmenu-qt firefox-globalmenu thunderbird-globalmenu indicator-appmenu
This will restore application menus in right place.
UPD: there might be a few packages I missed. To find them, open Synaptic and in the search field enter "appmenu", check the found packages for removal, then search for "globalmenu" and remove them too.
Restart/relogin into your X session to finish changes.
Also check this article.
There is a simpler method. Just type
sudo apt-get remove hud
in Terminal. It will remove all the other packages and you will get what you want.