i have a 500gb internal, so i've got plenty of space on my main computer, and then i've got a back up/old/pretty much unused 140gb computer, which i store some on, and then i've got a 500gb external which i filled so i recently (like 2 months ago) bought a 1tb external. at the moment i think i'm okay.

before i bought the 500, and before i upgraded to a computer with a 500gb internal, i only had that 140gb of space, and then i would only save the good stuff and delete the rest. but now i don't have to do that.