Okay, I wasn't really wondering; just kinda-sorta, you know? Like, the way I always start second-guessing myself after I spend way too much money on something.
Basically, what I learned today was that while the glossy Vaio magazine ads look really cool, the machine itself, compared to the Mac, is a clunky, antiquated boat anchor. My PowerBook has a much larger screen, a much larger touchpad, nicely rounded countours, a more ergonomic keypad, is about half the thickness, seems to weigh less despite having a larger screen, starts up in less time, and doesn't make all those horrible grinding clunking "DOS startup" noises. The Mac has more ports (USB, Firewire, ethernet) that are easier to access, and even a better designed AC power input. And the lid fits better; the Vaio has about a half-centimeter gap even with the lid closed. The catch release for the PowerBook lid is much nicer, better integrated into the case, than is that of the Vaio.
In short, after several months of ownership, I am continuing to find myself ever more pleased with the PowerBook. I did something right for a change!