Interesting, but the MP3 player market seems to be somewhat of a fluke in terms of resisting commoditization. Perhaps it's due to the iTunes marketplace keeping Apple's product line superior, in which case the iPad + App Store combo could end up doing the same. Then again, the iPhone doesn't have the market share that the iPod does, and I think iPhone market share will peak and then drop as Android and other mobile handsets come online that are truly competitive.
On the other hand, businesses generally buy PCs because they're far cheaper, but the market for MP3 players in a business context is basically non-existent, whereas it's potentially huge for the tablet market, so that's another mark against Apple.
It'll be interesting to see how it all turns out.