Couple of discussions regarding the Powerbook vs iBook question:
Good summary in the later link:
* 12 iBook its cheap and very good. If you cant afford more, get this one.
* 14 iBook its bigger, heavier, and more expensive than the 12. I still trying to figure out why this is in production.
* 14 Super iBook its bigger, heavier, and slower than a PowerBook. No idea why they make this one either.
* 12 PowerBook its a really expensive, slightly upgraded iBook.
* 12 PowerBook w/ Super Drive this is a nice model and you might need the Super Drive.
* 15 PowerBook This is a great computer for the price.
Furthermore, there is some mention that the screen of the 14″ iBook can be blurry. Maybe both a 12″ iBook and a 15″ Powerbook is the sweet spot? π