A few years ago I resigned myself to the fact that every thing about me, probably even my DNA sequence, is out there on various systems and will get stolen or compromised one day. I do what I can to keep things secure, but there's only so far I'm willing to go. If you have been reading a few security blogs over the last few years, you'd know that more and more experts (whoever they are) are recommending that corporations focus more toward mitigation of security breaches while taking resources away from prevention. It's kinda like getting mugged or in a car accident. Eventually, it's just going to happen to you. This is how we live in 2015.
Backing up to DVD or thumb drives or whatever is so 1990's. You may as well have a stack of Zip disks. Physical media is as stealable as anything else in your house. And BTW, if you do get burglarized, guess what the first thing is that they take? That's right, any box in the bottom of your closet or in your garage with a lock on it.
The cloud is technology agnostic so format doesn't matter, you shouldn't have to worry about that. It'll evolve over time but that's not your concern.
Buy yourself a little NAS, load it with 4-5 fat drives. Put everything important on it. Back your laptops and PCs up to it. Encrypt what you feel like encrypting. Push it all to Glacier, which costs a penny per GB. Done. No trips to the bank. No wasting time burning media that will degrade. No physical items to lose.
It probably is a good idea to have more than one copy of everything, just know that as soon as you make physical media of something, it's outdated. Someone else on this thread mentioned keeping a NAS at someone else's house, perhaps your grandma in another state. I'm personally not that paranoid about my stuff so I don't do that, but it's probably a good practice.
Fewer and fewer laptops are coming with dvd/bluray drives built in. Over the last decade we have seen fewer and fewer models of external drives/burners in stores. The writing is on the wall. In perhaps a decade or two you won't have choice, your stuff will be in the cloud (or whatever they change the name to), may as well get on that business now.