That's what people always say "I don't need that". Or "who needs a billion terrabyte iPod". No that is not the way to lok at the problem. You should ask "what could I do with billion terrabytes?" Well, for one you would NOT need to download very much because the iPod would come pre-loaded with every song, track, video and move ever produced in the last 100 years, you'd only have to download new stuff.
Wait 100 years, by then the price of billion terrabytes will be close to zero.