I use openbox when I need to save resources or when compiz breaks down, but I didn't want to install all of lxde or any of lubuntu.
You can put together a fairly decent desktop with just openbox and lxpanel:
To start lxpanel with openbox, add it to /etc/xdg/openbox/autostartYou probably want to use indicators, so install the plugin:
sudo apt-get install openbox lxpanel
There's a configuration/customization manager for obenbox:
apt-get install lxpanel-indicator-applet-plugin
I haven't installed an alternate file manager, but you might want to because:
apt-get install obconf
If you open nautilus, it will daemonize; replace the desktop menu, and draw a background. You can killall nautilus to get the menu back, but the background will remain drawn. To avoid this you need to edit /usr/share/applications/nautilus-auto-run-software.desktop, nautilus-folder-handler.desktop, and nautilus-home.desktop were each has a line:
Change it to
I wouldn't advise altering nautilus.desktop, because it will affect the default desktop as well.
Exec=nautilus --no-desktop something