Herman, you must have been hearing all the talk about Dropbox lately? I use it and it works great. As some commentators have been saying, if you want secure data then don't have data.
For cloud backup I would absolutely go with a brand name and not some fly by night operation (not commenting on Spideroak as I know nothing about them). Amazon S3 is the most reliable (they aren't going away) but it requires some technical knowhow to use.