Like Jim said, it's a bit impractical if you're thinking of backing up all of your stuff regularly to the Cloud.
I suggest getting a large external drive and something like GoodSync Pro (file sync/backup software). You set it up once to schedule backups of your folders unattended (assuming you leave your HW powered on).
Alternatively (or supplementally), you can use something like Macrium or Acronis to do regular backup images of your system partition/drive, as well as your data folders. I highly recommend this approach, as it will save you from having to reinstall the O.S. ever again.
For multiple drives or a network, NAS is the way to go. Of course, the more advanced setup, the more $$ you'll have to shell out. At minimum, you should be backing up your system partition and important data, which should fit on an inexpensive external drive.