FINALLY!!!! This has been a long time coming
Once upon a time, when the PC was young and IBM ruled the roost, the PC was the tool, and the OS was a choice you made. In those days PCs were either made by IBM or they were 100% IBM compatible. Initially you could choose PC-DOS (IBM), MS-DOS (guess who) and of course CP/M (no one chose this - voluntarily at least).
Somewhere along the line (yes I do really know this history, I was in the industry from the beginning of the PC 'revolution') MS Windows birthed. The initial version was nothing more than a graphical front end for DOS. However Windows 3 and then 3.11 really moved Windows into the modern age. By the time that Windows NT came along - incidentally killing OS/2 along the way, the fates were sealed. Windows was here to stay. Since then Windows 95, 98, 98SE, ME, NT 3.1, 3.51, 4, Win2K, XP and now Vista (aka MEII) have continued the line. One thing has been a common thread through all of these iterations of Windows. It was Microsoft calling the shots. Not the user. Not the hardware makers. Not Intel, and certainly not IBM on who's PC the entire industry is based. Microsoft has become used to being the top dog. Everyone else was a commodity supplier and had to bite it.
Finally though, someone has had the courage to push back, and not only that, so have consumers. Windows is/has become a commodity. What do we do with our PCs? Games? Internet? Music? Other Media? Work? When the PC was born it was all work and very little play. The OS was important because it was how we got access to the things we work with. Now though it's more of a launcher for our game software, the Internet browser we use or the media browser. Windows isn't in any way essential to any of these tasks. Windows is little more than a collection of APIs for games, and the browser has become central to information access and even the OS itself. Only in the work environment is much of Windows itself actually important. Windows has thus become something of a commodity. People - consumers - no longer need Windows to access the Net, music, movies, pictures or games. Any OS with a browser can manage it. Games consoles provide gaming, even to the point of Direct X or Open GL compatibility.
So, now finally, Microsoft has to face what the PC makers and Intel faced a long time ago, they are the provider of a commodity. Their trouble is that they simply don't act like it, nor do they want to accept it. Vista marks the first time when users really began to ask why they needed to upgrade. Why spend another $200 when XP is working out just fine? Why have to learn all the new crap for Vista when they're quite happy with XP? Why pay for a new version of Windows when they already have a license for XP? Why purchase an OS that makes it harder to use your PC than the old one, and comes with more restrictions on what you can do with your own hardware?
So, finally, a PC manufacturer pushes back, and there's absolutely nothing that MS can do about it. If one or two other PC makers follow Dell's lead, I think that consumers will realize that they too have some power in this situation. Finally, perhaps Microsoft will have to act like a supplier of tools and not a monopolistic monster who can do as they please and damn the consequences. I'm not holding my breath on this one though. Microsoft has an arrogance that makes even Sony look humble. And by god, that is not an easy thing to do.