xgl

compiz gnome ubuntu edgy eftI read a lot of HOWTOs about this topic, but no one satisfied me, so here's my version.
NB: I'm sure this howto isn't perfect, but it worked for me so it could also work for you specially if you have an Nvidia card.

I've been heavy inspired by this and this HOWTOs, Don't mix them! I also restarted a lot of time the xserver-xorg server.

I assume that you already have the proprietary video driver installed.

Installation

#Add this to your repositories

deb http://www.beerorkid.com/compiz edgy main-edgy

Then:

wget http://www.beerorkid.com/compiz/quinn.key.asc -O - | sudo apt-key add -

sudo apt-get install compiz xserver-xgl libgl1-mesa xserver-xorg libglitz-glx1 compiz-gnome cgwd

Create /usr/bin/startcompiz with:

Xgl -fullscreen :1 -ac -accel glx:pbuffer -accel xv:pbuffer & sleep 2
# Start GNOME
exec gnome-session --display=:1

Create /usr/bin/startxgl with:

#!/bin/bash
cgwd --replace gconf &  compiz --replace gconf decoration wobbly fade minimize
\ cube rotate zoom scale move resize place switcher &
sleep 3&
gnome-settings-daemon& # this is an hack because this daemon crashes

sudo chmod 755 /usr/bin/startxgl
sudo chmod 755 /usr/bin/startcompiz

Create /usr/share/xsessions/xgl.desktop with:

[Desktop Entry]
Encoding=UTF-8
Name=XGL
Exec=/usr/bin/startxgl
Icon=
Type=Application

gnome-session-properties

Add to 'Statup Programs' /usr/bin/startcompiz

killall gdm

..and now You should be able to select XGL session on gdm

Extra installation

sudo apt-get install gnome-compiz-manager cgwd-themes

Possible errors

compiz.real: GLX_EXT_texture_from_pixmap is missing
Probably you are using Xorg instead of Xgl; be sure use are using Xgl session

Small fonts, gtk theme standard,..
Probably gnome-settings-daemon isn't started, try with: gnome-settings-daemon&