Storage is cheap!
I'm not comfortable with having my personal data (regardless of encryption) stored off-site. Heck, you can buy a 750GB External Drive from Best Buy for $169 and perform the same functions. You can move it from one system to another, etc. The biggest problem I see with having it stored offline is getting to it. Obviously, you will need a high-speed internet connection, etc.
Anyway - that's just my 2cents!