Well, it's just a potent mix of the underdog religious fervor with the rightful heir/whatever theme
Right Ed, you hit the nail on the head.
Really the PC Whiny Crowed are really more devoted than the Mac people on any day and at any time, to the point they are vicious - just read any comments from any Mac product review on just about any web site..
Case in point, I was verbally assaulted, from a PC, IT person when I mentioned I owned a Mac - he said (Mac People are Stupid)
<-- that gives you an indication on how devoted they are to their PC's.
What we see today, IMO, is people excited about iPods, iPads and iPhones - not really about Macs per-say. Sorta its more about Apple the (Digital Life Style) not about Apple Computer.