External Hard Drives

[crapmyster]

Hello People,

I'm stuck! I thinking of getting a external hard drive, but as I dont much about these things I need somone help.
I would like 1TB of memory and could you tell what to look out in a external hard drive such as which processing speed is good enough and how ventilated it needs to etc. Just some guidelines I go about with, so I can get a good enough one which will last me a reasonable amount of time.

thanks
crapmyster