While this year may be too early, I'm 95%+ certain that Apple will be ditching x86 for ARM designs in the future. The (first?) rumors (from two independent sources) are linked
here, along with Intel's public acknowledgement of Apple's threat to switch platforms.
Leaving aside the iPad 2, which can meet most consumers' computing needs today,
this roadmap puts Nvidia's ARM based SOC at 5x its current performance by early 2012, increasing to 50x just two years later.
Finally, we have the cost differential, with today's A5 clocking in at $
14, vs. somewhere north of $
200 for the Sandy Bridge CPUs in todays Macbook Air. With Apple's average gross margin of 41.7%, that's a difference of about $350 in selling cost - before you add the retailer's margin.
Given this, it should come as no surprise that Intel is looking at providing
foundry services for Apple's SOCs.
Most of the arguments I've seen about why this this can't or won't happen are worse than the ones claiming Apple would never leave PowerPC for Intel.