A number of people have experienced problems with getting nvidia and compiz to work in LMDE. The following is a brief summary of successful techniques I've tried to get it all working on various machines.

First let me say that I like that LMDE comes without compiz enabled. It makes the live session really responsive and gives you something to think about when you have it up and running. Do you really need compiz at all if you don't use 3D? Gnome composting does a nice enough job if your answer is no. I can take or leave most of it but unfortunately I'm an absolute sucker for transparent menus. I can live without the rest.
 

Getting compiz to work with intel cards

sudo apt-get purge xserver-xorg-video-nouveau xserver-xorg-video-nv

sudo apt-get install libgl1-mesa-dri libgl1-mesa-glx

sudo dpkg-reconfigure xserver-xorg

Reboot or restart X :)
 

I've also been editing a script originally developed by ikey that does the same job. I'd be interested to know if there are any bugs with it. Testing at my end seems ok :)

wget http://omnsproject.org/scripts/intelfix.sh

chmod +x intelfix.sh

sudo ./intelfix.sh
 

My nvidia experience

The following is for the 17xx legacy driver but it should be a similar process for the 195xx driver as well. I'm not 100% sure what order I had to install these because of dependency issues but basically I installed the following:

nvidia-vdpau-driver nvidia-settings nvidia-kernel-common nvidia-xconfig nvidi-kernel-legacy-173xx-source nvidi-kernel-legacy-173xx nvidi-glx-legacy-173xx nvidi-kernel-legacy-173xx-dkms

I believe nvidia-kernel-common and nvidia-vdpau should be installed separately first, then the rest.

Before rebooting remove:

xserver-xorg-video-nouveau and xserver-xorg-video-nv

Reboot into new kernel then run nvidia-xconfig and nvidia-settings. Restart X.
 

Testing and starting compiz at logon ( adapted from this post at the LinuxMint forums ).

Test compiz is working by running alt-f2  then the following coomand:

compiz --replace

If that fails run the command in a terminal to get error messages.

Once you are happy with the way compiz is working create a new entry in startupp applications with the same command

compiz --replace

If you're feeling adventurous mmesantos1 and ikey have created a startup script that does a nicer job. Either method will work.

Create and add this script to your startup applications. Don't forget to make it executable.

#!/bin/sh
echo “Get Some”
if [[ `pidof compiz` ]]; then
# compiz running, nuke it.
metacity --replace &
killall -9 compiz
else
# no compiz.
compiz --replace &
fi

N.B. in LMDE the are no options set in the compiz control panel. You'll need to set these up to your liking :)