I had installed the proprietary fglrx driver that's seen in System > Administrative > Additional Drivers. This left a watermark in the bottom right of the screen, so I followed the steps I saw somewhere (do not remember where) that said to download the latest catalyst driver, extract it, and copy the config file from the extracted catalyst driver to /etc/ati/config. So, that's what I did. When I did it, the watermark was gone.
I started having a lot of issues with freezing then though, so I re-installed ubuntu at that point and started running it with the watermark stlil on. (in other words, with the only change being the Additional Drivers proprietary fglrx driver). I found that I started getting freezes still with this, but it seems like the freezes are directly tied to if I am running on battery power. If I am on battery, it's almost unusable, and if I am plugged in, I don't seem to experience them. I do not know where to look to see why this is happening.
Since the platform is recent you'd be better off with something featuring a more recent kernel.
Kanotix might be a good suggestion, though since it's Kano's distribution I don't know how objective he is
If you feel more adventurous you might try Ubuntu's daily image.
You can always come to irc://irc.freenode.net/#kanotix and get latest infos about Kanotix. I am definitely sure that what we currently develop will be something very interesting for binary 3d driver users. But if you really love U 10.10 you can use my script there too. It is tested up to kernel 2.6.38:
I made it even more easy to install as when you always have to reboot because of active kms driver you just need to do:
sudo sh install-fglrx-debian.sh
which is also allowed to execute inside x. You can force older drivers with -v VER option like:
sudo sh install-fglrx-debian.sh -v 10-7
or whatever you like to try. I usally enable all kernel compat patches for older drivers too, but tested iso only the current one. When a fglrx driver is found you can only execute the script from a vt1, but as it often crashes from switching from one driver to the next you may want to use -z option (does not kill x) and reboot in that case.