My new 12" Powerbook has arrived and I'll have more to say about the wonderful features it has later. But on the topic of OS X as an operating system here's the score so far. I have attached many "windows only" devices to it and they have all been recognized quickly by the Powerbook.
Here's the list: 60GB Firewire Harddrive (formatted for Windows), Zip Drive (disks formatted for Windows), USB Keychain storage device, 2 digital cameras, and a Treo 300 phone.
None of these devices needed "drivers" in order for the computer to recognize them. They just worked. It was much easier to set up software to work with these devices on the Apple system.
Oh, it's true that my dad's iBook didn't immediately 'see' a Microsoft USB optical mouse when it was plugged in. That one did require installation of drivers, which were on the Windows formatted CD-ROM. And it worked fine after I installed those drivers. Makes sense that OS X wouldn't see that one right away because Apple uses one-button mice so it had to be told how to handle that additional feature.
One thing you hear a lot from people who switch to Apple is how "stuff just works." I've got a pretty clear picture now of what they are talking about.