So it's official - Apple decided to Think Different.
I'll let the masses comment, but an interesting tidbit is the developer platform: a 3.64 GHz P4. This seems to imply that there will be nothing out of the ordinary with the actual Intel based Apple hardware (i.e. they're not going to be using XScale chips or other non-x86 chip). Jobs talks about moving applications to be mostly just a recompile - for CPU intensive apps I think that's under-estimating the endian-ness issues a bit.
Overall, this looks like a nice move for Apple and Intel.