Well, I gave PCBSD 9 (LXDE) a whirl, and it doesn't have all the bells/whistles/candy that KDE has, but it is Fast, and stable !

Hardware: Desktop, with nvidia 9800GT
- 1st thing was boot into VESA.
then from the LXDE-Desktop; "PC-BSD Control Panel" -> "System Manager" -> "Tasks" ->
Fetch System Source (All)
Fetch System Ports Tree
now, since Linux emulation, is loaded by default in any pcbsd 9 installation.
I then tried to install the latest freebsd-x86_64 drivers (290.1.*) directly from nvidia's site, but the "make install" simply failed saying it doesn't support FreeBSD 9.0 Release yet...
huh, or wtf ???
So instead, I had to use the "nvidia-driver" (version 285.09.05) from the FreeBSD "ports", which is still fairly new.
-ok, (as root) , inside each ports dir below:
/usr/ports/x11/nvidia-driver/
/usr/ports/x11/nvidia-settings/
/usr/ports/x11/nvidia-xconfig/
... just run "make install clean"
/usr/local/bin/nvidia-xconfig
(this should update /etc/X11/xorg.conf)
In the /boot/loader.conf file, and just after the "# Load File-System Support" lines I added:
# Load nvidia kernel mod
nvidia_load="YES"
...now Reboot.
Select #6, "Run the Display Wizard" and then just select "nvidia", instead of "vesa" this time, and set my resoultion to 1920x1080, (yours might be different), click Apply,
it works beautifully.

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The above is NOT a de-facto Howto regarding nvidia driver installation on pc-bsd 9.
but on my setup, this is how i got nvidia drivers installed, and more importantly, working great.
now why the latest nvidia proprietary drivers (290.*) from nvidia's site failed ? -I dunno.
If anyone has a better way to do this, feel free to correct/suggest anything.
Cheers.