nVidia didn't work that easy for me either (...as always with Fedora)
They should really fix their kernels and stop blaiming everything else. A missing <linux/config.h> in the fedora kernel (but still available in the ones from kernel.org) is what breaks the installer.
FC6 also doesn't seem to like all nvidia cards. The link posted by Void Main shows the same problems I had:
http://lunapark6.com/?p=2454 (I'm using an nVidia FX 6600 GT as well).
Basically, it didn't fully set up the sections "Module"(only "load glx existed) and "Files" in xorg.conf (X did work though).
After installing the nvidia drivers (the testing ones from Livna, the stable ones don't work with compiz), gnome-display-properties claimed my refresh rate was only 50Hz
I used the nvidia-settings tool for rebuilding my xorg.conf file and correcting the refresh rate.
It added :
Section "Files"
RgbPath "/usr/X11R6/lib/X11/rgb"
ModulePath "/usr/lib/xorg/modules/extensions/nvidia"
ModulePath "/usr/lib/xorg/modules"
FontPath "unix/:7100"
EndSection
Section "Module"
Load "dbe"
Load "extmod"
Load "type1"
Load "freetype"
(Load "glx" was already their)
In order to get the borders in compiz to work, I also added
Option "AddARGBGLXVisuals" "True"
in Section "Device".
Right now, everything is working in exception of "gnome-display-properties". It still lists 50Hz while "nvidia-settings" shows 75Hz...