this is another one, but using Openbox. It will reduce the idle RAM usage to aprox. 22mb.
apt-get update
apt-get install openbox vnc4server iceweasel menu obconf obmenu
mkdir /etc/vnc
echo 'openbox-session' > /etc/vnc/xstartup
reboot
vncserver
the last step will ask for a pwd, use it for VNC. Optional, create a user, log in with it, and then run vncserver, so the session is not rooted.