No. There's very little on my drive that is simultaneously both unrecoverable through some other means and of vital importance to me.
If I was going to recommend a backup solution to someone else, it would vary based on their needs. A RAID-1 configuration should be more than sufficient for any consumer, plus it can speed up IO by roughly a multiple of how many drives are in the array. Someone running a server of some sort might be better served by a RAID 5 configuration, which would increase uptime in case of a failure. A developer might want to have a more traditional backup solution, in case something important gets deleted or overwritten.
For medium or large businesses, you want the best of all worlds. RAID 5 or 6 (depending on whether performance or fault tolerance is more important) as well as weekly offline backups stored offsite.