Is the Dell/Microsoft Alliance Fracturing?

An anonymous reader asks: "Dell has historically been the most loyal of all Microsoft's partners. Even today, it is very difficult to avoid paying the Microsoft tax on most of Dell's desktops and notebooks. Recently, two things have made the news where Dell is not toeing the Microsoft line. First, was the announcement that Dell is trialling shipping desktop and notebook PCs in the UK with Firefox as the default browser, instead of IE (announcement confirmed here). Today we have news that Dell is not going to support HD-DVD, despite reported incentives that recently induced HP to do so. So, what are some theories as to why Dell has lately been less of a friend to Microsoft, and what does this mean for the future? Does it mean that it might soon become possible to order Dell's full line of personal systems with Linux installed, or no OS/FreeDOS to save the Microsoft tax?"