I've heard alot of people ask how to use a different window manager (WM from here on out) in a desktop environment like GNOME or KDE, but I never really heard an answer, so a few manpages later, I have it down for GNOME and I think I have it for KDE. (This tutorial is going to be using Enlightenment as the WM, I haven't tested any others yet, but I'm sure it'll work for other WM's also.)

In a file called /etc/profile, there's a line that, on my box, looks something like:

Code:
export PATH USER LOGNAME MAIL HOSTNAME HISTSIZE INPUTRC
Now, right before that line, add

Code:
WINDOW_MANAGER=enlightenment
or whatever WM you want GNOME to use

or

Code:
KDEWM=enlightenment
then add WINDOW_MANAGER (or KDEWM) to the export line, so it'll look something like:

Code:
export PATH USER LOGNAME MAIL HOSTNAME HISTSIZE INPUTRC WINDOW_MANAGER
or

Code:
export PATH USER LOGNAME MAIL HOSTNAME HISTSIZE INPUTRC KDEWM
now restart your computer, fire up GNOME or KDE, and enlightenment should be your WM.

Hope this helped,
n0t t00 elite

PS, when you use enlightenment, the GNOME desktop is just anonther window as far as E is concerned, but it's stickied by default, so Alt+Right-Click the desktop and click Stick/Unstick, and then the GNOME desktop won't follow you everywhere.