If you like Gnome but would like to try a different window manager with your Gnome desktop, here is a way to do it

In Ubuntu when you install a new window manager you access that new window manager by logging out of your current session and logging into a new session with that window manager but the new session does not use your existing Gnome desktop. But what if you want to use the new window manager with your existing Gnome desktop. The key is to  replace metacity, the default window manager Gnome uses with the new window manager.

 

Here is how.

1. Install the window manager you are interested in with your preferred package manager.

2. Open the file ~/.gconf/desktop/gnome/session/required_components/%gconf.xml

It should resemble the following
<gconf>
<entry type="string" mtime="1226369905" name="windowmanager">
<stringvalue>metacity</stringvalue>
</entry>
</gconf>

3. Change the value between the stringvalue tags for windowmanager with your desired window mangager

The following example would change the window manager to pekwm

<gconf>
<entry type="string" mtime="1226369905" name="windowmanager">
<stringvalue>pekwm</stringvalue>
</entry>
</gconf>

 

4. Save the file log out and log back in and the new window manager should be running.  To revert back to the original window manager just edit the file again and place metacity between the string value tags  for windowmanager.