I still have my PowerBook G4 and think it's better whenever I use. If only the G4 was fast enough and if developers were still making more PowerPC apps then I could still use it as my main computer. I'm curious to know why Apple decided to go with chicklet keyboards. I don't hate them, but I've noticed that I can type faster on the G4. It's also a more comfortable keyboard in my opinion.
I think that was all about the unibody. If you have to have a big open area in a plate of metal, a whole bunch of small holes gives much more strength than one huge hole.
I know the whitebook got it first but I bet Apple was already thinking about the unibody construction at that stage. Chicklet keyboards came into fashion at that time (Sony started them as far as I remember). And Apple like to try things out before they go for something all the way.
I do believe the old curved keys were better in some ways, for one it's much easier to feel if you're not hitting the key dead on because the slant feels different. But the flat shape looks cooler and we are talking Apple here.
I have to say it took me some time to get used to them, I even bought a spare old-style 'crumbcatcher' Apple keyboard for my Mac Mini just before they were discontinued, just so I wouldn't have to move on to the chicklet ones when my keyboard would break. But by now I've come to hate the crumbcatchers, they type so heavily compared to my wired chicklet keyboard and the click is actually less defined. Oh, and it gets annoying that they double as a display case for assorted crumbs and dust
PS: If you really wanted to, you could probably make do with a last-gen non-unibody MBP which had the same keyboard and were reasonably fast compared to the old G4's. But it wouldn't be worth the tradeoff for me.