Mine

Section "Module"
    SubSection  "extmod"
        Option    "omit xfree86-dga"   # don't initialise the DGA extension
    EndSubSection
        Load        "dbe"       # Double buffer extension
        Load        "type1"
        Load        "freetype"
        Load        "glx"
	Load	    "dri"
EndSection
# **********************************************************************
# Files section.  This allows default font and rgb paths to be set
# **********************************************************************
Section "Files"
        FontPath   "/usr/share/fonts/misc/"
        FontPath   "/usr/share/fonts/TTF/"
        FontPath   "/usr/share/fonts/Type1/"
        FontPath   "/usr/share/fonts/75dpi/"
        FontPath   "/usr/share/fonts/100dpi/"
EndSection
# **********************************************************************
# Server flags section.
# **********************************************************************
Section "Extensions"
        Option "Composite" "Enable"
EndSection
Section "ServerFlags"
       Option "Xinerama" "True"
EndSection
# **********************************************************************
# Input devices
# **********************************************************************
# **********************************************************************
# Core keyboard's InputDevice section
# **********************************************************************
Section "InputDevice"
        Identifier      "Keyboard1"
        Driver  "kbd"
        Option "AutoRepeat" "400 40"
        Option "XkbRules"       "xorg"
        Option "XkbModel"       "pc105"
        Option "XkbLayout"      "us"
EndSection
# **********************************************************************
# Core Pointer's InputDevice section
# **********************************************************************
#Section "InputDevice"
#    Identifier "Mouse1"
#    Driver     "mouse"
#    Option "Protocol"    "IMPS/2"
#    Option "Device"      "/dev/input/mice"
#    Option "Buttons"    "5"
#    Option "ZAxis Mapping" "4 5"
#EndSection
Section "InputDevice"
        Identifier  "Mouse1"
        Driver      "evdev"
        Option      "Buttons" "7"
        Option      "ZAxisMapping" "6 7 5 4"
        Option      "Device" "/dev/input/event1"
        Option      "Dev Name" "Microsoft Microsoft Trackball Optical"
        Option      "Emulate3Buttons" "no"
EndSection
# **********************************************************************
# Monitor section
# **********************************************************************
Section "Monitor"
        Identifier      "Envision"
        HorizSync       30-86
        VertRefresh     50-160
        Modeline "1600x1200" 229.5 1600 1664 1856 2160 1200 1201 1204 1250 +HSync +Vsync
EndSection
Section "Monitor"
        Identifier      "ProView"
        HorizSync       30-86
        VertRefresh     50-160
#       Modeline "1600x1200" 229.5 1600 1664 1856 2160 1200 1201 1204 1250 +HSync +Vsync
EndSection
# **********************************************************************
# Graphics device section
# **********************************************************************
Section "Device"
        Identifier  "nvidia_left"
        Driver      "nvidia"
        VendorName  "nVidia Corporation"
        BusID       "PCI:1:0:0"
        #for aiglx/beryl
        Option      "AddARGBGLXVisuals" "True"
        Option      "RenderAccel"       "true"
        Option      "NoLogo" "True"
 
EndSection
Section "Device"
        Identifier  "nvidia_right"
        Driver      "nvidia"
        VendorName  "nVidia Corporation"
        BusID       "PCI:1:0:0"
        #for aiglx/beryl
        Option      "AddARGBGLXVisuals" "True"
        Option      "RenderAccel"       "True"
        Option      "NoLogo" "True"
EndSection
# **********************************************************************
# Screen sections
# **********************************************************************
# Any number of screen sections may be present.  Each describes
# the configuration of a single screen.  A single specific screen section
# may be specified from the X server command line with the "-screen"
# option.
Section "Screen"
    Identifier  "Screen 0"
    Device      "nvidia_left"
    Monitor     "ProView"
    DefaultDepth 24
    Subsection "Display"
        Depth       24
        Modes       "1600x1200"
    EndSubsection
EndSection
Section "Screen"
    Identifier  "Screen 1"
    Device      "nvidia_right"
    Monitor     "Envision"
    DefaultDepth 24
    Subsection "Display"
        Depth       24
        Modes       "1600x1200"
    EndSubsection
EndSection
# **********************************************************************
# ServerLayout sections.
# **********************************************************************
Section "ServerLayout"
    Identifier  "Simple Layout"
    Screen 0 "Screen 0"
    Screen "Screen 1" LeftOf "Screen 0"
    InputDevice "Mouse1" "CorePointer"
    InputDevice "Keyboard1" "CoreKeyboard"
    Option "Xinerama" "on"
    Option "Clone" "off"
EndSection

Section "DRI" 
    Mode    0666 
EndSection