The fastest way to replace GNOME's Metacity with XFWM4 in Ubuntu.

I replaced Metacity with XFWM because:
1. XFWM is faster. Xfce is much faster than GNOME, but I'm not using it because I have dial-up and I can't download such size(20+ MB). So I must replace window manager to make Ubuntu a little faster.
2. It supports built-in compositing. It can make menus, inactive windows, ... transparent without Compiz so I can use compositing on OpenGL-incompatible video card.
3. It has easy theming. XFWM uses XPM(X Pix Map) and PNG formats and a text file to create themes, unlike Metacity, that uses XML that I badly understand.
OK, let's start.
1. In Synaptic install package "xfwm4". Also, if you want to choose themes, install "xfce4-settings". Then if you want to run XFWM Settings, run: "xfce4-settings-manager &" in terminal.
2. Go to System->Settings->Startup Applications.
3. Click "+ Add".
4. In Command field, enter : "xfwm4 --replace".
5. Type something in Name field.
6. Click "+ Add".
7. Reboot and enjoy:).
As you will notice after reboot there will be a black screen for a short time. It's because autostart is not done immediately after log in. But it's the fastest way.

How to set proper resolution and refresh rate in Ubuntu

During the startup of X server if the horisontal sync isn't set up, sometimes resolution isn't properly detected, because the driver uses default horizontal sync range. To change the hsync and refresh rate, you must edit the "/etc/X11/xorg.conf" file. Open the terminal and run "gksudo gedit /etc/X11/xorg.conf". In the Monitor section add two lines:

HorizSync 30-81.4
VertRefresh 60-100

to be able to select maximum resolution 1680x1200 and refresh rate 100. If you want the max. resolution to be higher then change 81.4 to something higher, for example 110 and if you want higher max. refresh rate, change 100 to the needed number. Next save the file and reboot. This doesn't work for LiveCDs.
EDIT:  Found this solution to work with a Nvidia GeForce 6600GT video card: http://forums.fedoraforum.org/showthread.php?t=254139