You can either tear out your hair when a disaster strikes your hard drive or you can prepare for it ahead of time, but data loss is as inevitable as death and taxes. An online backup service is one of the best ways to protect yourself against such threats as a crashed hard drive or accidental deletion. Natural disasters such as fires, floods, and earthquakes can also spell the end of your digital media and documents. Even if you're among the very few who diligently perform local backups at regular intervals, you could still lose data if you don't store backups offsite.
Backblaze earned praise from many of you for being easy to set up, even for non-technical people. It's built for people who want to get their data backed up, without being forced to search for error codes and cryptic status messages whenever something goes wrong. To that point, Backblaze backs up just about everything on your system. You get some control over what's backed up and what isn't, but the point is to be fast, easy, and hands-off, so everything on your system—documents, music, video, external drives you have plugged in, just about anything. Instead of telling what they do back up, Backblaze actually has a special page dedicated to what they don't back up instead. Backblaze offers unlimited storage for your backed up data, and while by default it only backs up files smaller than 4GB, you can bump that up if you need to. Like other online backup services, it runs in the background, backing up your data all the time (or when you schedule it to, if you prefer), and your data is encrypted so only you have access to it. It supports Windows and OS X, and is smart enough to de-dupe data, do incremental backups, and keep backup processes low on system resources. You can read more about Backblaze's features here.
An online backup service's speed depends on how quickly it can encrypt, compress, and upload files to its servers. This should be of particular concern if you need to back up (or restore) a large amount of data. A high-performance backup service also minimizes its effect on network and system resources. Make sure to check out our speed test results in the review of any service you're contemplating using. Backup speed should not be the sole determinant of which online backup service you use, but fast upload speeds can certainly make initial and subsequent backups less disruptive.
SpiderOak's beauty is that it's a combination cloud syncing and storage service as well as a backup client all in one. Unlike some of the other services though, you'll have to pay for the storage you use. You get 2GB for free just for signing up, and you can get up to 10GB by referring friends. SpiderOak Plus nets you 100GB for $10/mo to use for syncing and backups, and every 100GB after that is another $10/mo. Plus, you can connect as many computers to any SpiderOak account as you want, so you're not paying by the system. You can read more about SpiderOak's plans here.
In addition to the 5 GB free option, OpenDrive has one consumer-grade plan called Personal Unlimited. It costs $9.95 /month and offers an unlimited amount of storage space for your backed up files. Prepay for one year at $99 to bring that down to $8.25 /month. You can add an additional computer for $9.95 extra /computer, up to three extras for a total of four.
It may take some time depending on the number of files you have and the total size. You can use the "Email me when done" option to get notified once the archival completes. You can then download the created archive locally. Make sure to download it to your Google Drive shared folder or copy it there after download so it gets synced and backed up in the cloud.
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.