Apple's most underestimated strength is their continued march towards vertical integration - buying make the right processor company (PA Semi) and a team of 150 processor gurus to minimize power use, developing a proprietary manufacturing process to make seamless aluminum notebooks, etc, etc etc.
A good read from 2008 about Apple's strategy . . . http://www.forbes.com/2008/04/24/mitra-apple-pasemi-tech-ent...