Tony Fadell, the man credited with creating the iPod and iPhone, is leaving Apple for personal reasons, according to the company.

Fadell, who at one point was rumored to be a possible successor to Apple chief Steve Jobs, will be replaced by former IBM executive Mark Papermaster, who joined Apple as senior VP of devices. IBM is suing Papermaster for violating a non-compete clause. Fadell will remain associated with Apple as an advisor to Jobs.

What's interesting about the transition is the contrast in expertise of the two executives. Fadell's forte was in consumer hardware, which played huge dividends in the sleek design and interface that propelled the iPod to its dominate place atop the portable media device market. Papermaster is more focused on building processors and servers - the backend guts that consumers rarely see.

Judging by these differences alone, one could speculate that Apple is satisfied that future iPod models will continue to maintain a dominance in the market regarding design aesthetic, and will now aggressively pursue a new model of music and media delivery that relies on connected media, opposed to the current downloadable-file model.