I use a paranoid approach:

1. Main storage is a server using a RAID array.
2. I use robocopy to copy data to a workstation with a larger hard drive using a scheduled task. Here is a link if you are interested in the free tool from Microsoft: http://www.microsoft.com/en-us/download/details.aspx?id=17657. Way better than xcopy.
3. I use cloud-based backup service
4. I use robocopy to copy data to an external hard drive using a scheduled task. The external hard drive is located on a shelf positioned right by the most likely fire egress door. I call this my 'run for your life' backup.

I also make it a habit to clone and replace hard drives every three years in my server. I just recently started moving my workstations to solid state hard drives.

IMO, for backing up it's best to have multiple strategies rather than relying on one strategy.

One is none, two is one...