All PowerBooks Go Extreme
Apple announced its new 15-inch PowerBook G4 model today, which is AirPort Extreme ready in the cheaper version and includes an Extreme card in the more expensive configuration (see specs). The 12-inch and 17-inch models were also refreshed. All the models now also include Bluetooth built-in -- no more dangly USB bits.
This leaves just the consumer iBooks as the only non-Extreme models; they're also the last remaining G3-based systems that Apple offers. The eMac, iMac, PowerBooks, and Power Mac lines are all sped up.