Envy is just a set of scripts that use the nvidia installer and configure xorg.conf (as far as I can tell). It worked great for me with a Geforce 6 integrated system (after suffering through trying to get xorg configured properly, and all of the correct modules loaded).
But, as always, YMMV
:)

Thanks to all of you guys. The problem with beryl was that somehow my xorg.conf was changed (i don't know when) but I was assuming the configuration was good cause i checked it before. Once i added all the 3d options my beryl started working again.

etch and nvidia
 

when i typed grep "EE" /var/log/Xorg.0.log i get;
(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(II) Loading extension MIT-SCREEN-SAVER
(EE) Failed to initialize GLX extension (Compatible NVIDIA X driver not found)

If you are having a problem you should start your own new thread ..