I feel funny saying this because I have been pro-PC for years and years, but pretty much if your main focus is creativity as in art or music the Mac is the way to go, if your focus is gaming or pirated software, the PC is the way to go. As the gaming continues to move away from the computers and onto the gaming platforms I see the need for computers to fade away so eventually the Mac will take over, provided nobody else throws something unexpected in to the ring, but this will probably still take many more years.
Now that Steve Jobs is gone, Apple could make the PC completely obsolete in a short time if they wanted do, simply make Mac completely open source hardware. If they did that, nobody would have a PC anymore, but I suspect that is why Bill Gates bought many shares in Apple long ago, because doing so would kill the PC practically overnight and deal a harsh blow to Microsoft.
Question is, if they did that now, would Bill let it pass? Microsoft has enough other irons in the fire, they could adapt away from the PC platform... maybe. They might have to learn to make code less buggy. (this might kill them)