Make multiple secure backups of your keys (encrypt the backups). I store mine on an encrypted drive and two USB keys - learnt my lesson when I lost 100K BLK through not keeping multiple backups.
Actually in the wizard i recommend two backup methods. Emailing your keys to yourself and using an optical drive. Like a DVD. Because old hard drive backups will fail and expire after a couple years. It happened to me and i lost an immense amount of data. So DVDs dont expire especially m-discs. Also another way is to print out the contents of the file on a piece of paper.