The last announce by the IE Team will originate a big discussions I think: Internet Explorer 7 will be distributed as an high-priority update via Automatic Updates.
This is an important decision in terms of security (all the Windows installations that works with the old IE version will be updated in a simple manner) but this is a decision that will have some countersides.
The first is that all the web applications that will be developed must be absolutely tested under the new environment, in order to avoid problems when IE7 will be the default choice for lots of users.
The second is what I call "the same old story": by choosing this type of distribution system, I'm sure that someone will criticize Microsoft again for the browser's monopoly war. Guys, this in not a choice in order to be the most widespread browser, but this is dictaed only for security reason.
I hope that all will understand this... 