For those wanting to use more than 2G of ram and haven't the experience with linux I'd suggest running fedora, there seems to be fixes or updates they've applied that allow the nv driver to work with the 9500M GS chip set (I can't comment about any others), fedora supposedly uses KDE by default, although it looks/feels almost identical to Ubuntu which uses Gnome.
***BIG FAT WARNING***
Really don't do this unless you know what you are doing, Ubuntu and its package management utils will groan and moan a LOT, about a broken install because package names ubuntu packages depend on just won't be there any more. Usual other warning here about doing bad things, you should back up yada yada yada, proceed at your own risk and I went to all this trouble to type up this big fat warning so if you ignore it don't blame me!
***BIG FAT WARNING***
So with that out of the way and for those with a little more experience or simply don't care if they blow away their installation, and have too much time on their hands you can try doing what I've done, although I haven't fully succeeded yet I'm getting close. It's possible to download the fedora packages:
From there you run alien on all the rpms.
for i in `ls *.rpm`; do alien $i; done
Then you need to dump the ubuntu packages:
dpkg --force-depends --purge xdebconfigurator x11-xserver-utils displayconfig-gtk xserver-xgl xserver-xorg xserver-xorg-core xserver-xorg-dev xserver-xorg-input-all xserver-xorg-input-evdev xserver-xorg-input-kbd xserver-xorg-input-mouse xserver-xorg-input-synaptics xserver-xorg-input-vmmouse xserver-xorg-input-wacom xserver-xorg-video-all xserver-xorg-video-apm xserver-xorg-video-ark xserver-xorg-video-ati xserver-xorg-video-chips xserver-xorg-video-cirrus xserver-xorg-video-cyrix xserver-xorg-video-dummy xserver-xorg-video-fbdev xserver-xorg-video-glint xserver-xorg-video-i128 xserver-xorg-video-i810 xserver-xorg-video-intel xserver-xorg-video-mga xserver-xorg-video-neomagic xserver-xorg-video-nv xserver-xorg-video-openchrome xserver-xorg-video-radeonhd xserver-xorg-video-rendition xserver-xorg-video-s3 xserver-xorg-video-s3virge xserver-xorg-video-savage xserver-xorg-video-siliconmotion xserver-xorg-video-sis xserver-xorg-video-sisusb xserver-xorg-video-tdfx xserver-xorg-video-tga xserver-xorg-video-trident xserver-xorg-video-tseng xserver-xorg-video-v4l xserver-xorg-video-vesa xserver-xorg-video-vga xserver-xorg-video-via xserver-xorg-video-vmware xserver-xorg-video-voodoo xorg-x11-fonts-100dpi x11-common x11-utils x11-apps
From there it's just a matter of installing the packages alien spat out that you need:
dpkg -i xorg-x11-server-xorg_188.8.131.521-30.20080415_amd64.deb xorg-x11-server-utils_7.3-4_amd64.deb xorg-x11-server-common_184.108.40.2061-30.20080415_amd64.deb xorg-x11-fonts*.deb xorg-x11-filesystem_7.3-2_all.deb xorg-x11-drv-nv_2.1.8-2_amd64.deb xorg-x11-drv-nouveau_0.0.10-3.20080408_amd64.deb xorg-x11-drv-mouse_1.3.0-3_amd64.deb xorg-x11-drv-keyboard_1.3.0-4_amd64.deb xorg-x11-drv-evdev_1.99.1-1.5_amd64.deb xorg-x11-drivers_7.3-5_amd64.deb xorg-x11-apps_7.3-4_amd64.deb
At this point you might have to --force-depends a few fedora converted packages to get them to install but there shouldn't be too much more to do than I've posted above.
At this point you should be able to kind of get the nv driver to works, although I'm having problems with frequency or something fiddly like that making the screen and mouse go a bit funny, but for the most part it is almost working.
The nouveau driver needs a kernel module loaded to work, although I was planning to try and get this working rather then messing about with the nv driver since the nouveau driver is an opensource implementation that is supposed to have some 3D support.
It'd be nice if nvidia would help speed this effort up because at this stage I can't in good consciousness recommend their products to anyone even remotely thinking about linux. I've found out since ending up in this predicament what I thought to be true, they are the last graphics manufacture holding out and I should have opted for ATI instead.