I love my iBook, but I'd give it up in a second for a Powerbook. If I were you, I'd stick with your iBook for now though. The Powerbook 12" has no L3 cache, which gives it's G4 much of its oomph in non-Altivec software. Believe it or not, the G3 750Fx in the iBook is pretty potent in most applications. It's capable of using a 200MHz memory bus and 1GHz clockspeeds. In fact, you can overclock it by software if you can get your hands on the CHUT 1.1.1 tools. Apple is holding back its full potential so that the Powerbook's G4 looks more attractive. Anyways, the new Powerbooks are probably going to be released in the WWDC in a couple of weeks. Hopefully by the fall, the PowerPC 970s will show up in the Powerbooks (if they aren't released at WWDC in 2 weeks which is highly unlikely). I'll jump up to a Powerbook when they get a PowerPC 970. But for now, the only Powerbook that is compelling to me is the 17" one and I find that is too big for my needs. If you wait a couple of weeks, the new 15" Powerbook may be out and could suit your needs better. It will have the sturdier, more scratch-resistant aluminum casings of the 12" and 17". And it will probably have a "real" G4 with L3 cache, and better graphics chip.
I got much the same reaction by people so far as the colour was concerned. But once people start using it, they fall in love with it. I definitely didn't buy my iBook for its looks, but they've grown on me nonetheless.