My gut has been in sync with Michael's and I have only recently begun to even consider the use of a cloud for Backups only, even then only if distributed across many distinct clouds after being locally converted to at least 5 striped logical disks in a Level 6 RAID. The 5+ disk images would be individually encrypted LOCALLY prior to being separately backed up to their 5+ respective clouds.

To reconstruct my data, an intruder would have to locate the data from at least 3 of my providers and decipher at least 3 different keys. Conversely, I could withstand the failure of as many as 2 providers and still recover my data. By encrypting locally, my encryption key would never exist in the cache memory of any cloud server, nor would any clue as to the schema for the striped array of an unknown number of disks.

Introducing BRIC (Bunch of Redundant Independent Clouds):
http://bitcartel.wordpress.com/2012/10/21/rbic-redundant-bunch-of-independent-clouds/

Redundant Array of Independent Clouds: Share To Cloud Mapping
https://tahoe-lafs.org/trac/tahoe-lafs/browser/git/docs/specifications/backends/raic.rst

Welcome to The Least-Authority File System
https://tahoe-lafs.org/trac/tahoe-lafs

I don't know why some people call me paranoid.