Ubuntu does well with either ATI or nVidia; both media chip makers provide Linux drivers which are available online. With Ubuntu Linux driver installation is very easy because once installed Ubuntu has built-in application ('envy' I think) which searches and installs automatically the latest available ATI or nVidia driver in the internet.
You can also choose from various distributions (distros) which offer varied advantages depending on your computing needs. Try visit distro watch: http://distrowatch.com/
The best way is to install and run your Ubuntu on a partition, anyway meanwhile, you can try other Linuxes from separate partitions until you can make your final decision which of them you prefer. The free software world offers you many choices, yet they're free!
FOSS? No, this report is aimed to discourage free software use and encourages to buy and use commercial (M$) systems. This is a matter of decision to you. Example: I can scare you to hell from using Linux/Unix and fool you into Vistra if Bill pays me well.
Don't pay attention to hypocrites.
Hope this helps. Ahalan.