[sf-lug] Running "standard" X-windows in addition to Gnome / KDE?

[RBV]

Hi:

I'm having problems getting "standards-based" X-windows (I'm not even  
sure of the properly terminology) to run on my Ubuntu system as a  
third GUI choice.

My Ubuntu 7.04 (Feisty)system currently allows me to use the GUI login  
panel to start either Gnome (preferred) or KDE (primarily for fun)  
sessions.   My standard method of running these two GUI desktop  
managers is to boot into Gnome, then create a virtual terminal and use  
the GUI to login into a KDE session in a virtual terminal.

So far, so good.

Now I'd like to add a standard X-Windows login choice but haven't been  
able to identify what and how to install and configure the plumbing  
necessary to do that.  My usual problem-solving approach -- Web  
searches -- hasn't been all that helpful since the articles I've found  
assume that X-windows has already been installed and is running  
properly.

Can anyone point me to the Ubuntu Repository resources and associated  
configuration "how to" information that I can use to install and  
configure a working X-windows GUI on my computer?

Cheers & thanks,
Riley
SFO