1.33GHz and 1.5GHz PowerBooks will probably be faster than your 867MHz PowerBook. Only the 133MHz FSB vs 166MHz FSB will make a lot of different. I would prefer you to get the 1.5GHz one since you will replace it with a 867MHz PowerBook. A faster computer must make a bigger different. Also, the new 1.5GHz model comes with the new trackpad, 5,400rpm Hard Disk, Bluetooth 2.0 and 8X SuperDrive.