Dude, come on. Just go get like a 1TB external drive, USB powered if you wanna be convenient. Copy all the stuff to it that you want to keep and put it on a shelf somewhere, then plug it back in and copy more stuff to it if you get more stuff, or overwrite the old stuff if you get updated stuff, and delete the stuff you don't want to keep anymore. You'll probably end up buying a new one with room for more stuff because you have too much stuff, long before the drive dies of mechanical failure, provided you don't leave it plugged in. (Which you shouldn't).
And no, you won't really benefit from an SSD here. They're too expensive per GB for backing up stuff right now.