Is it possible to install ubuntu12.04 normally and then disable the desktop environments somehow, so that startx doesn't bring up unity or gdm or anything like that? I'm aware of ubuntu alternative and ubuntu minimal, but I'm asking if I can get startx to bring up just a window manager or whatever I tell it to in .xinitrc after having installed ubuntu with unity.

If possible I would like to leave unity or something installed so that I can bring it up if I want/need to, but not have it/gdm come up by default