I find it hard to believe that there are still people who don't seem to grasp the concept of adequate data backup.
One of the advantages of file based audio is given a sensible backup strategy you should always have available perfect copies of your music and be largely immune to theft, physical media damage,loss and if your smart even sticky fingered rugrats.
3 copies on separate drives is the minimum sensible option as Clive advocates.
If you must use your computer as a storage device then partition it so the operating system and applications are on one partition and your data is on another.
Keep passwords, email addresses, site logins and profiles on a flash drive.
About the only thing i keep on the computer hard drive these days are games simply because unless you have a fast SATA connected drive some games just wont render fast enough to be playable on external storage.

It really doesn't matter what method you use to backup; what's important is that you do it.