just to add my 2 cents
Psychologically, this was a big blow to me. I just don't like the idea of "Intel Inside" my Mac.
But I agree with those who beleive this will be a good thing for Apple. Apple has been plagued from early on with poor chip makers. IBM proved to be worse than Motorola in many ways, particularly because a) the competition for computers has become much more intense in recent years, and b) Apple has gained so much mindshare because of the success of the iPod. Intel has tons of R&D money and will be able to provide high yields and fast clock speed -- both areas where IBM fell far short.
But that's in the long-term. In the short term, Apple is in for some real difficulties. I predict flat hardware and software sales for the next two years as people wait to see what shakes out. I know very little about Rosetta, but I just don't buy that it will be perfectly seamless. Running Classic in OS X was okay, but it wasn't seamless in many cases.
I see many people either holding off on purchases of new Macs for the next year or two, or at best making interim purchases of lower-end consumer Macs to get them through the transition. I have an original G4 Yikes that I have been wanting to replace but for lack of money. At this point, even if I scrape up the cash I think I would rather buy an inexpensive Mac mini to tide me over, even though it is a far cry from the dual 2.7 G5 that (until today), I badly want.
I haven't checked the markets yet, but my prediction is Apple stock slightly down, Intel slightly up.
All in all, while this should have been done years ago, it's perhaps not a bad time for Apple to make the chip switch. If the success of the iPod can hold relatively steady it will give Apple a bit of a cushion with which to weather any transition problems. I'm looking forward to an iPod video and a movie download store in the near future to bolster sales. But the Intel news now means that Apple is going to have to really sell its computers on design and the strength and ease-of-use of its OS. Although many have argued that the different chip architecture between Macs and Wintels meant that many potential switchers believed that Apple was woefully behind in the megahertz war, I think (perhaps incorrectly) that many people did realize that you couldn't just compare clockspeeds to get relative performance numbers. Within two years, however, you will. This might make it more difficult for Apple to sell hardware that, on the outside, appears much more expensive than the cheap offerings from Dell and Gateway.
And how long before someone figures out a way to run OS X on a Dell x86, despite whatever roadblocks Apple/Intel may throw up?