russed said:sorry to say this but you are wrong there. USB 2.0 is theoretically faster as in 440 kbps but that is only in very short bursts whereas firewire can sustain 400kbps for longer stretches hence firewire external hard drives are far better than usb 2.0 ones. fact.
Whilst you are correct that Firewire is a lot better than USB2, not least because Firewire is way more efficient and also does a lot of the work itself (USB2 offloads it to the processor), it doesn't mean that external firewire hard drives are better than USB2 ones, and this is sadly down to the most popular combo Firewire/USB2 controller chips being CRAP at Firewire. To get decent performance you have to use the Oxford Firewire-IDE controller, but this is a lot more expensive.
How fast can the hard drive in the iPod write? I'm sure that both USB2 and Firewire are capable of saturating it.