I agree with everything the participants had to say. I avoid using Classic and 9 as much as possible, because the contrast with OS X's power, beauty and flexibility is too stark. I only boot 9 to transfer digital photos (Kodak's fault for giving half of their cameras non-standard interfaces, including my DC 240). I only use Classic when I need to do some serious work in Word. (Boy, do I hope the OpenOffice port to OS X is successful!) Otherwise, with iTunes, BBedit, OmniWeb, Mail, GraphicConverter, Terminal, etc., <Dick Vitale voice> it's OS X all the way, baby! </Dick Vitale voice>
Speaking of the Terminal, I'm a long-time Mac user, but since getting the PB, I've been delving into the Unix command line. Once you get over the baffling inattention to mnemonics and standard interfaces, it's a gas. You're basically programming on the fly with your OS. The power is incredible.
Love the Dock, especially with the HUGE improvements Apple made after the PB and the as-yet-unsupported option to move it to the side. Could have done without the return of the wildly overrated Apple menu, but I understand why Apple had to cave in on that one. I also agree with the participants comments about moving away from the desk top. I use it a lot on my Windows machine at work because it's the only area where it's relatively easy to customize the organization of my files. I used it to a lesser extent on OS 9. On OS X, I have found no need at all to use it for anything but a backdrop.
"One last thing": I have a suggestion for a future chat: the early stages of application development for OS X. I think it's really interesting how some new (OmniGroup) and long-time but small (Bare Bones) Mac developers are "getting it," while some of the heavy hitters (*cough* Adobe *cough*) are clearly not.