Dell has launched an XPS and Studio notebook with Ubuntu Linux 8.04 factory installed.
The two models are the Dell XPS M153On and Studio 15n. Dell "recommends Windows Vista Home Premium" for both of these models, according to the Dell web pages for similar models.
Here's the quick blurb from Dell's popular Dell2Dell blog:
"Today is the day. For customers in the United States who interested in compelling notebooks with 15.4” Hi-def widescreen displays the Dell XPS M153On and Studio 15n notebooks are now available with Ubuntu 8.04 factory installed," according to the blog posting, by Daniel Judd, product group strategist.