As some have mentioned, hardware wallets are really cool. I've heard great things about the Trezor and Ledger Nano but I don't have experience with them. I'm also worried about long term data integrity and I'm not sure how their backups work. I use Electrum for my cold storage, personally. Good luck!
Trezor's backup consists of 24 seed words (+ passphrases for increased security) that you need to write down and safely store as a backup. That's all you need to restore your wallet to a new Trezor or software wallets with Trezor import support (eg. Electrum).
I have no experience with Ledger, but I assume it's not much different.