G4/Powerbook vs. new ibook, is the g4 really that much better than the new 600 ibooks? Options

[radiohead]

hello. I am about to get a mac. i am looking at all of the available systems. Im looking at the new ibooks as the most accessible way to go ..with lots of ram. it looks like a great deal to start recording on. But if i knew that a G4 tower or powerbook was that much better i would try and get that. basically if the new ibooks are comparable to the g4s..i would get an ibook. Does anyone have suggestions on whether a laptop or tower would be better? And any info on ibook vs powerbooks would be appreciated. i just dont wanna get an ibook and be disappointed i didnt pay more for a g4 later, you know ? the new G3 ibooks have 600proc. and i would get like 256 or more ram. ive seen powerbooks with 400 G4 processors..and equal ram..anyone know the difference? thanks for any help cause buying a computer is a big deal you know. thanks again. justin