External hard drives (USB) always seem to need an external power
adapter. That's very clunky and hard to carry around.

Are there external hard drives that don't need external power?

I know that there are some drives that don't need an external power
adapter when plugged into *two* USB plugs at the computer. However,
that's not an option for me since my two USB plugs are at two
different sides of the laptops.

Is Firewire the way to go?

Thanks!
Markus