Imac Or Ibook For Music? Options

So, I'm a pc-man, but SO tired for PCs... I think I'm not the only one... So I've been thinking about a mac. I make music with computer, so I need some power, but also stability (which PCs don't seem to offer...). I can't afford those G5s or even G4 (the one which look like computer, not iMac, eMac, or laptop...). PowerBook is too expensive too. So my choices are iBook and iMac. I thought about the 800Mhz G4 (12") iBook, or maybe the 933Mhz G4 one. How big is the difference in speed of those two iBooks? I would probably take that 640mb memory (which is the maximum) for those. So is the 933Mhz one worth the extra 200-300€ (or something like that in $s). And then the other one choice is the iMac (15") There's 1Ghz G4 processor in that and the maximum ammout of memory is 1Gb, which is more than in iBooks. Also, the memory seems to be a bit faster in iMac, because it's DDR 333Mhz, while it's DDR 266Mhz in iBooks. That iMac would cost about 1600€ (again, something like that in dollars), whit 1Gb memory (if I won't buy that memory from apple, cause they seem to have quite expensive memories). So, which one would be the best choise (price/quality ratio)? And can you say, what kind of pc do those macs match, (I know that the Mhz-ammount is not compareable). If you bother answer, I would really appreciate that, cause I really don't know anything about macs, and I don't believe in salesmans speaks.