I currently have 33,000 photographed and catalogued on my Windows PC. My solution is as follows:
Catalogued in Adobe Lightroom, using sidecar files for my Raw Images and embedded keywords for the JPGs(not many of these).
Lightroom creates copy/backups of the Catalogue automatically once a week which I retain for 3 months with in my Work Directory.
For backups I use the following
Syncback Pro : which automatically backs new and changed files (several methods of Comparison available) from up my Work Folder (Photographs and all other Documents) to my NAS drive each evening. Plus once a week I syncronise my Work Folder (and other key data) to 1 of 3 External 1Tb Harddrives which are kept in a Firesafe in my Garage.
I also use Syncback to back up all my other drives (4) to the NAS daily excluding C which is backed up every 2 days to an other internal drive using Acronis True Image and then copied to the NAS.
There is a simple rule you can not have too many copies of your important files.