It kinda depends on what you wana use it for. (other than storing data
) E.g are you going to want to take some of the data on there round to a friends or something.
I have an external drive i share with my dad and it's great to just quickly put a few files on there and take it round a friends. Although it is kinda like a glorified usb stick if you use it this way.
Oh and do you have an internal one already or are you using as your main/only HDD?