I used my dropbox for really important files. But then all the rest is archives and don't mind it getting it next day. All my external hard drives never last more than 2 years. While it is an interesting approach I am concerned about reliability if it is an archive.

I tried out Bitcasa for Mac and it is terrible. My Finder basically stop responding after bitcasa started. I have been working on a simplified version of AWS boto library for glacier, in the goal of making an open source tool like a command line sftp/ftp style access to glacier.