I used to be obsessive about this.  At work I was backing up twice a day when our IT dept thought that once a month was adequate.  Now I  only have to worry about my home PC I back up when I ever I have new data that needs preserving.  I use Roxio purely because it has a drag to disk function. 

I guess that you're looking for some all singing all dancing automated package but if you're not the basic stuff that comes with your Windows package will do.  And if all else fails just copy it using Windows Explorer.

The important thing is not "how" but "when" . Certainly everytime you create new data.  And then at regular intervals.  The more frequent, the less likely you'll miss something.

Just remember this salutory tale of a friend of mine.  He was writng games abck in the '80s.  He backed up regularly.  After three months he took all the floppies down to his employer.  Every single floppy was corrupt.  He had backed up blindly with out checking to see that each operation was successful.