I recommend printing out too. Crossposting from something I posted to reddit here, especially since I have direct experience with digital data going bad on supposedly stable mediums (e.g. CDRs.)
Reasons for using a simple paper wallet instead of digital data
1) Inheritance. If you were to die very unexpectedly from an Aneurysm, will your family (A) know you have Bitcoin, and (B) know how to retrieve it? Paper wallets make this easy. You just keep a copy of your paper wallet in the safety deposit box / safe along with precious jewels and cash.
2) Longevity. Have you ever dealt with obsolete data before? I have. Here's a sampling of what I've experienced in the past 29 years (no exaggeration) of dealing with my own data:
I've had to recover data on obsolete media (5.25 floppy disks) stored in obsolete formats, with limited success I've had to recover data on gold-plated CDR's subject to "bitrot" because the manufacturers didn't realize that CDRs would oxidize after as little as 10 years, again with limited success
I've run around in circles trying to preserve data when interfaces change. I've still got masses of data on 8mm tapes written with SCSI drives and I have no idea how I'll ever recover it.
When you commit your data to an encrypted thumbdrive, or an encrypted cloud service, or whatever digital medium, you are also committing yourself to shepherding that data from medium to medium as the technology evolves. Talk about "human error"! USB will not be around in 10 years. Nor dropbox.
Specifically, what's a proposal for storing information in way that will be safe and relevant for 20 years without having to migrate your data to more modern media every so often?
When you commit your data to a piece of paper, you get to rely on 1000's of years of human experience regarding how to keep paper, jewels, cash, etc. safe without being screwed over by technology or hackers.
Disclaimer: I'm the guy behind https://bitcoinpaperwallet.com so obviously I'm totally biased. :)