Personally I've just got 4 Drobos loaded up with 19 hard drives, and external hard drives to back those up to, which stay offline otherwise.
I don't back them up as often as I should, but the Drobos can lose a drive and be fine as long as it's replaced before a second drive dies.
I'm still screwed in the event of a house fire or other major disaster though.
Storing it all on someone else's server in another state would be a good idea, but then you've got to pay for that every month and it'd take freaking forever to upload so many terabytes of data I've already got - on a good day I can get around 100mbps download speeds, but only ever 10mbps upload max (and usually less than that) - and if I tried to upload 24/7 for weeks I'm sure Charter/Spectrum would throttle the connection even further.