Ohh, right... okay so it wasn't the first one with IDE. :-) Heh, learn something new everyday.
I do know for a fact that Apple prided themselves on the fact that most of their systems ran SCSI though. ;-)
As for the PPC vs Intel thing, well... it's very much a horses for courses market, but per MHz, PowerPC does generally outperform Intel systems. My understanding though, is that Apple was getting impatient waiting for low-power G5 CPUs to be developed for use in their laptops, and hence decided to make the switch.
Backward compatability will be interesting though... I wonder how their newer machines will keep up when they're trying to emulate a PPC. ;-)