I know well and good that Ubuntu was conceived because Shuttleworth felt that Linux was ready for the big time and that Red Hat etc had too much penchant to devote resources into low-level bickering that ultimately had relatively little effect on your average end user instead of focusing on improving user experience, but now that Ubuntu has moved the user experience so far forward, they should reconsider that mission. The places where Linux is most lacking is low-level compatibility for things like fast 3D acceleration and power management.
Canonical should use some of its funds (aka "Mark Shuttleworth's money") to buy the 100 best selling laptop models each year, set rigorous testing standards, spend six months developing a new release and then take however long is necessary to make sure that everything passes on the last three years' best selling laptops. In this process, they should not be shy about contribution to X, kernel, etc., and should distribute patched versions of these if necessary to get compatibility.
That, combined with Ubuntu's user experience work, is what will really make Linux a completely viable desktop computing platform. Far too often things break between releases and/or upgrades.