I would be hesitant to use RAID without a solid backup strategy as well. If you have a drive failure, you may have a hard time finding a single replacement drive. If you start carrying a spare drive on the shelf, then your costs just went up.
After my brother's house burned down (no one was home) and they were able to retrieve only some of their memories, it hit me that backing up my documents and storing them next to my PC was only protecting against hardware failure. Also, I was less than consistent in backing up my documents to an external USB drive.
A couple of years ago, I went with a $50/year online encrypted storage. I chose Carbonite although it's been a couple of years since I've researched the vendors. I've been very happy with the service and have had to do a full system restore and got all of my documents back.
They only back up (by default) your content. That means your digital photos, Word docs, spreadsheets, multimedia, etc. You can select other files for backup (programs, etc.) by selecting them within Explorer. What I like is the second a file changes, it is queued up for backup to the continuously running system with a file watcher component. There is no thinking about what I need to back up and when. It just works.
I still maintain a full backup to USB drive in the event that I need to perform a complete system restore. I would have that backup + the up-to-date Carbonite backup. When I had to do my disaster recovery (due to my own stupidity in converting a disk to Dynamic partition), I received a workable system between the two backup systems, although it had a few issues as would probably be expected.
I guess my two cents would be - If your home PC contents are valuable to you, protect them likewise. Now that all of our family photos and videos are on the PC, I want to protect them in the event of some calamity to my home that would affect an on-site backup.