If you type
Code:
james@home:~$ ls /etc/X11/xinit/
README.Xmodmap xinitrc.fluxbox* xinitrc.twm*
xinitrc@ xinitrc.fvwm2* xinitrc.wmaker*
xinitrc.blackbox* xinitrc.kde* xinitrc.xfce@
you will get a list of environments you can start with. To choose any one of them from a command prompt without X already running (runlevel 3) simply type, for example,:
Code:
startx /etc/X11/xinit/xinitrc.xfce
foo.bar, above, is correct about how to change the default window manager/desktop environment for a single user.