Over the last few years I have come to believe the following statement: "not everybody who uses Macs is smart, but everybody who is smart uses Macs". Last week at CES in Las Vegas, of the hundreds of attendess I observed using laptops or tablets, I saw one person using a Windows laptop (although it could have been a Linux machine :)) . CES was like a "Windows free zone" except for the Intel booth. I am sure there were a few more Windows machines but I did not see them being used by attendees.
Another observation is that early adaptors of the iPad are switching to the MacBook Air for their daily computer and using the iPad less. I am in that group. I only use the iPad for book reading and presenting. See this post for why I present with a tablet.
I also think the iPhone may be declining in popularity amongst early users. Saw a lot of people at CES who had an iPad or MacBook and a Samsung Galaxy smart phone. I think the quality of integration with Google services is leading people to high end Android phones.
BTW--have not seen many Windows machines amongst MIT Sloan students this week. Apple all the way.