What about Altivec?
My first reaction to this is "THIS SUCKS!". But I think if this is done correctly, it might turn out to be OK.
The biggest concern I have is for the support of Altivec. In the sciences, vector processing is utilized heavily. And just from the benchmarks I've seen, algorithms that leverage Altivec are much, much faster than the equivalent on the Xeon or Operton.
My second biggest concern is with the compilers. It looks like they are going to be using the Intel compilers over GCC. Will these compilers:
1.) be free?
2.) be as ANSI compliant as GCC?
My preference would've been to move to Intel (well, I'd rather it was AMD) in the consumer lines (iBook, Mac Mini, eMac, iMac) and keep the G5 in the Power line and perhaps upgrade the Powerbook to G5 or Freescale G4. However, if they are moving everything to Intel, I hope they at least add the Altivec engine to the Pro-line of machines. This would at least give power users a real reason to stick with Apple, while people intersted in consumer-line products would continue to be interested in Apple because of style and form factor.