Turns out the USB ports in my computer weren't USB 2.0 (probably 1.1). I figured this out when I saw the transfer speeds off L's laptop.
So now my machine has a four port USB 2.0 card (five if you count the one which is only accessible inside the computer - can anyone explain that? :)). iPod updates, external hard drive backups... it's all flying.
This is awesome. Wish I'd twigged a bit sooner!