Tim Bray anticipates the potential for a shift in the browsing landscape, posits: "We need a tight, crisp 'Use a Better Browser' button that has a mouse-over and is linked to a message somewhere, and the message is simple: If you were looking at this in any browser but Microsoft Internet Explorer, it would look and run better and faster."
Cool. Only problem is, I don't think it's true. Yet. I spend a lot of time in Mozilla on Windows and Mozilla and Safari on the Mac. Other than pop-up blocking and tabs, I still find the browsing experience better when going back to IE6. It's more solid and more likely to have everything work (granted, partially because people make designing for it a higher priority — but also because more things work or have worked for longer).
I also don't think we should kid ourselves about the evolution of IE stopping. Yes, there will not be an IE7. That doesn't mean, when you run Windows Update in three months, there won't be an IE service pack in there, does it?
Not that I disagree with most of Bray's arguments. The field has changed in an interesting way, and I don't think MS's lock is guaranteed. I really like this statement: "People, on average and in the long term, aren’t stupid and aren’t patient and aren’t cowards." This is counter-intuitive, but if that weren't true, Microsoft wouldn't be in the position they are today.
See also: Anil's Upon the demise of Netscape, which encourages Google to get in the game.