When Mac sales increase while the rest of the PC market decreased that's call taking market share. But what would Apple know about taking market share anyway? I mean they barely were able to tap the MP3 market taking "only" about 90% of of stand alone MP3 player market.
And now they're exponentially taking market share from the cell phone industry.
If Apple continues to grow their computer market and the cell phone market, that alone makes the upside tramendous. To say nothing of what they might release in the future, given their track record for innovation.
Good luck trying to bash the price down so you can buy in. I think now is the time, but wait if you want.