None of the services can prioritize backups based on a goal size for a month, either, which can be an issue with bandwidth caps, already imposed by Comcast (250GB per month, inbound and outbound combined), and with other service providers rolling them out in test markets. This would likely affect you only for an initial backup, but hosted backups should reflect the current broadband market's limits.

It's not paranoid to worry about your backup data being intercepted, or being retrieved by other parties from your hosted storage area. Each storage company has various security protocols in its software, on its servers, and in its companies to prevent access to data. Nonetheless, it's a legitimate concern.

All services except iDrive and Jungle Disk first encrypt data on your computer using their software, whether it's the first backup of a file or an incremental piece. Most services then use 128-bit SSL/TLS, the same encryption used for secure Web transactions to transfer data. In iDrive's case, the company uses the SSL/TLS transfer, and then encrypts data when it arrives on the server. Jungle Disk uses secure transport, but makes file encryption optional. (There are no known cracks against 128-bit SSL/TLS, and any discovered would affect all e-commerce and banking transactions worldwide.)

Backblaze, CrashPlan Central, Mozy, Jungle Disk, and SpiderOak all offer one additional level of paranoia: you can set your own password to encrypt files on your computer. The service then has no idea what your password is, and no cracker, government agent, or other party can decrypt your files. Lose this key and, just like an encryption key used with desktop password software, you're hosed. (iDrive says it plans to add a password option to its Mac software.)