BackBlaze doesn't have an offline component, so you'll have to handle that yourself, but it's by far one of the most affordable options on the market. Accounts are $5/mo (you get a break if you pay up front for one or two years), and you can add more computers to the same account for another $5/mo. You can read more about Backblaze's pricing options here.
The iDrive service comes with backup clients for nearly every PC and device, including Windows Phone—a rarity these days. The company provides additional storage for syncing all your devices and PCs, allows sharing of files with anyone, and has the ability to back up to a local drive. The company also has several affordable pay plans. For all the details, read our full review of iDrive.
Most services encrypt your files with strong systems such as AES 256 before sending them up to the servers over an encrypted connection. The majority of products we tested also offer a private encryption key option. If you choose to manage your own encryption keys (basically the "key" that decrypts your backup), know that it is your responsibility to remember it. The online backup service itself will not be able to help you reset the password if you forget it. On the flip side, this means that no one (including employees of the backup service and law enforcement officials) other than you can unlock your backups. This is ideal from a privacy and security standpoint. Use a password manager to keep track of your private encryption key if you think you will forget it.