Memphis,
I've had a 12" iBook 600 pretty much since it came out. I have used it on an almost daily basis over the last two years, especially when I'm travelling, on planes across the country and back and forth to Europe, in some pretty rugged shoots in wild areas...and sometimes I simply didn't have the optimal protection for it.
I love this thing. It's my baby. Old reliable. No dead pixels even with the battering it's taken.
Believe me, when you buy a portable you're thinking about how amazing it would be to do A-Z on the thing. But in reality, you end up using it more and more for a relatively limited number of things. iTunes, Word, Excel, and the DVD Player (Mail, Safari when you're lucky enough to get a connection) will be your core apps when you're on the road. Yes, it will run Photoshop and you almost certainly will run it and other high-end apps for a while, just because it's a rite of passage to dump everything you own on a portable.
But for what you'll end up using it for, really, the iBook is absolutely kick-ass. IMO.
The PowerBooks are wonderful but overpriced.