Onboard audio should not be a problem with Ubuntu. For a long time, there were no Linux drivers available for Creative X-Fi cards. That kept a lot of people away from Linux. The situation has changed in recent months. There are now beta drivers available.

You may not need to install any Linux chipset drivers. I used to run Ubuntu on my old DFI NF4 board. Ubuntu gave me internet access and onboard sound without the need for additional drivers.