Apple today announced it was switching from IBM's PowerPC chips to Intel's Pentium line. I'm not sure what to make of it, but I think it'll be a make-or-break decision for Apple. If the transition goes smoothly, it could being a lot of new users and developers to the Macintosh platform. If it's at all rough or problematic, it could cost them many of their current user base and developers and send them into dark days once again.
I think it could hurt hardware sales over the next year or so, people could be understandably hesitant to invest in expensive hardware that features a dead-end chipset. I'm due for a new laptop soon, my old G3 iBook is just not cutting it anymore, and it's already made me decide to not buy a new laptop until the Intel transition is underway. So that's one less laptop Apple will sell over the next year or so.
Personally, I'm excited by the prospect that I might be able to buy a Mac that's as fast as a PC, even if it's a two year wait. My PC with an Athlon XP 3000 gets noticeably better performance that my dual 2GHz G5 in many of my key apps, and I'd love to get that kind of performance out of a Mac. Time will tell now if the bottleneck was the processor or the OS itself, I'm hoping for the former but suspicious it might be the latter.