I think Apple's market share overall won't change much, but Apple will seep in stronger into it's current market segments like education (where you find huge market shares - some universities have 30% Mac users!) and Graphic Design or small businesses.

The PC will survive because it can be shipped in cheap boxes for devloping countries, and MS has complied with a corresponding stripped-down version of Windows Vista (probably the only one that actually works).

I don't know Apple's corporate strategy, but it either is bringing new products to it's existing market, or exploring new markets with existing (or modified) products.

Or both, if they have the bandwidth and manpower.