External drives won't be faster than the ineterface you use. A latest generation PATA or SATA drive can go faster than current USB2 or Firewire (FW 800 can handle most drive's thruputs but there aren't many folks that have that yet). Now eSATA is here and is pretty much the same as connecting direct to the mobo. SATA II drives will have the advantage if you have that available. The nice part about using USB or FW is the portability aspect. Almost everyone has USB, many fewer have FW, and almost none have eSATA yet. I use USB because of its universality and I'm willing to put up with a slower trasfer rate. It's still as fast or faster than most other external storage methods.
.bh.