I am not very knowledgeble on linux ,but i have tested various distros in time.
Even though Ubuntu has a lot of attention for some reason i have never liked it and it never worked properly for me on my AMD CPU based system (thats what i ve had since 2002).
I ve always liked Simply Mepis or Mandriva.
Last time i tried Mandriva i was satisfied that everything was working including sound out of the box.
Maybe the guys at Ubuntu did not test something properly before releasing or some BIOS code update from Gigabyte broke some routine for Ubuntu.
If games would have worked under linux i would have used Mandriva most probable ,better looking desktop