The G5 was never put in any laptops. They where so powerful they couldn't find an efficient way to cool them in a mobile computer.
An iBook is for home users, while the Powerbook line was intended for video and graphic design work. The Powerbooks offered way more features than the iBook and where way faster. I have a Powerbook G4 1.67 Ghz, with 2gb of ram and a 1440x960 res display. For the time period (2005) that was insane, and is still relatively good these days. It does all the tasks I need it to do flawlessly.
Thanks for the info that was exactly what i was looking for. I thought iBooks were better for some reason :?. My Powerbook on 837MHz runs quite amazing aswell. That's one things macs win in is the afterlife.