In response to comments by the infamous “v” regarding Apples choice of Intel versus AMD; I think the answer can be found here and here.
Most of the platforms that will initially receive the Intel chips will be the small form factor and mobile machines, mostly due to Intel's brilliant Centrino CPU line. AMD do not have the lead that Intel does on the mobile platform yet; and it just makes sense for Apple to stick with the market leader.
The question is though; would you pay a premium for an Apple notebook given that you could run Windows on it if you want?