What's the general consensus on external hard drives. I am looking to set
one up as a backup device but not sure whether to go for a host powered USB
drive (in the region of 40 - 60GB) or go for a 120GB externally powered USB
drive.

Ideally I want a dive I can plug in and leave it do its incremental and full
backups without having to turn the power on and off at system start-up and
shutdown. What are the externally powered drives like for leaving powered on
all the time and is it advisable to do or not do this?

cheers

Butty