What is the difference between External Hard disk and Portable Hard disk?

[alijayad]

I need a external hard disk that will work without any fuss and just by plugging the USB cable. Which hard disk should i buy? I need a very cheap type with capacity above 500 GB. Please help me out here.

And by the way, how bulky are those hard disks with extra power supply to carry around? Are they a pain in the a*s or are they portable enough?

[Declan1991]

They will all plug and play these days, and come cheap. They are fairly portable, and you can even get really small ones (you mightn't get a huge capacity) that will power themselves from the USB cable.