Dell has laid out what we can expect from the Ubuntu distro they are going to install on their new Linux machines.

• The default software from the Ubuntu media will be installed on the system, including kernel and applications.
• The peripheral options offered with Ubuntu will be a subset of what is offered with other operating systems. We’re offering the hardware options on each system that have the most mature and stable Linux driver support. These hardware options have been thoroughly tested by the Linux team here at Dell.
• [...]
• At this time, we are not including any support for proprietary audio or video codecs that are not already distributed with Ubuntu 7.04. These include MPEG 1/2/3/4, WMA, WMV, DVD, Quicktime, etc. We are evaluating options for providing this support in the future.