I've been looking forward to this announcement for a while &mdash this is why I'm posting it here. I had expected (as many other people) that the first models to be converted could be the iBooks. Frankly, I'm glad they didn't do it, because I won't feel bad for having bougth this G4 just a month and a half ago. Don't get me wrong; it's working great ;-)
Other news include the update of Mac OS X to 10.4.4 (which I'm already running :-) and the release of iLife'06 and iWork'06.
I hope that NetBSD gets ported to these new machines and that it works as well as the i386 port. If that's the case, I'll seriously consider a Mac as my next desktop machine (which is still some years away... and who knows what will happen in this time frame).
Edit (17:07): I'm now wondering why the hell on earth many people seems to assume that Windows will run on these machines... All they have done is change the microprocessor (OK, plus other things), but this does not mean it becomes an IBM-compatible system — just consider Amiga-based and Mac-based 68k systems. I'm sure somebody will get it working, but it hasn't to be easy.
Edit (20:14, 12th January): I stand corrected. These Intel-based machines come with regular hardware as found on PC systems; i.e., they run standard Intel microprocessors and chipsets. The major difference is that they use EFI (the Extensible Firmware Interface) instead of the obsolete BIOS. Looks like Windows Vista will run on them directly (and Apple won't forbid it :-). As regards NetBSD, support for EFI will be needed as well as (possibly) some new drivers.