It wasn't really a jump. Apple's market share has been growing more or less steadily since the switch to Intel. IMO I don't think that Vista has had much of an

It wasn't really a jump. Apple's market share has been growing more or less steadily since the switch to Intel. IMO I don't think that Vista has had much of an effect on mac sales; it's primary competitor has been XP. All else aside, I'm sure that a significant factor has been the fact that you can run software for Windows on an Intel-based mac without emulation overhead. Another factor that I'm sure hasn't hurt is that after the transition to Intel systems, the macs reached something close to price parity with the Windows OEM's. In some cases, the mac ends up being the less expensive option (specifically, the Xeon-based rigs), which is also new territory for Apple.