I can't understate this enough.  Switchers or what Apple calls "New to Mac" are the fastest growing subset of Mac purchasers.  These buyers account for more than 50% of Macs sales in Apple's retail stores and I'd like to point out that Macs have been the most popular computers at many retailers such as Amazon.

Macs Notebooks and Desktops are Top Sellers at Amazon
Macs often take several of the top 10 slots in Amazon's top sellers list.  As I write this post, Macs account for 5 of the top 10 sellers in Amazon's notebook category and 8 out of the top 10 in the desktop category.  These are Tiger based systems!

I expect Macs to take up more slots in Amazon's top sellers categories once people can purchase Leopard based Macs without having to upgrade from Tiger.  The timing couldn't be better for Apple.  We're fast approaching the 2007 holiday shopping season and you can bet that in addition to the Leopard release on October 26, Apple has more up the marketing sleeve for customers.

New MacBooks soon?
I expect revisions to the MacBook in the very near future to really get Mac notebook sales in gear.  The MacBook line was last updated back in May so updates are likely.  A story today published at Engaget Apple's got a new 13-inch laptop prepped for Leopard launch?  highlights comments from TheStreet.com's Scott Moritz who says that Apple will release a 13-inch ultraportable laptop perhaps as early as next week to coincide with Leopard's launch.  He states that the laptop will be aluminum just like the MacBook Pros.

The end of the year will be off the charts for Mac sales.  The Mac base will continue to expand but at an increasing rate.  Our April 2006 prediction of at least 8% Mac market share by the end of the Leopard life cycle is looking more likely with each passing day.