Some info for y'all
A couple of things pertinant to the discussion that I learned while at MacWorld today:
One, the new 12" PowerBook is smaller than the iBook, by about half an inch on each side, and about an eighth of an inch thinner. When you see the two side-by-side (another attendee talked the apple guy into bring an iBook over to the pb display) the iBook looks a lot bigger, moreso than I would have thought from looking at the specs. And it's lighter by a bit, too. Also, the fit and finish is like a Lexus compared to a Toyota Corolla, not bad in either case, but you can feel the quality in the PowerBook.
Also, I got to talk to one of the Safari managers for a while. I asked him about tabbed browsing and he said that they've talked about it a lot, and thought about it, and that we can submit feedback about it if we'd like. He said they want to make page rendering so blisteringly fast that there's no need for tabs. And that they intend the "snapback" function to take on the functionality of following a link into a new tab for a while, and then going back to the original page. They're thinking that those two together (speed, snapback) will provide an alternative way of interacting with web pages that they thinks better. But like I said, they're open to feedback. I personally don't use tabs, I prefer to cycle through windows with cmd-~
Two more things to note - the metal appearance is because they didn't like the way the normal windows interacted with the web page and looked like part of the content. The metal provides more a definite distinction. There was a developer (not apple, an attendee) standing next to me having fits about it. Also, all the widgets are Cocoa - which seals the deal against Chimera for me, because I can actually type this reply and not go insane waiting for letters to appear on the screen.
Oh, and one more thing...

I overheard another Apple developer saying that they hadn't really focused on optimizing the rendering for speed yet! Sweet-O.