John Gruber has it perfectly right. A backup of your data is security.
"Over the years I’ve received numerous emails from past and former Genius Bar support staff, telling similar stories of heartbreak. Customer comes in, their iPhone completely broken, or lost, or stolen, and they had precious photos and videos on it. The birth of a child. The last vacation they ever took with a beloved spouse who has since passed away. Did they ever back up their iPhone to a Mac or PC with iTunes? No."
Don't be stupid and not backup your data. For My Eyes Only 7 and My Eyes Only Classic users we offer our Syncryption service. Yes it costs money. Every year in fact, but don't be cheap, don't be stupid. Backup your data. Strong words? Not at all.
"The problems here are multifaceted and complicated; “don’t trust anything in the cloud” is simplistic and, in its own way, dangerous."