As mentioned in my previous post as to Why and How To make disc images, I make backups of my most important discs – from Driver discs, Installer discs and even some movie discs. I could just as well burn these backup onto blank discs but most of the time I just load them up (or mount them) as virtual drives.
Even if you don’t make your own disc images, some software-makers are now opting to use ISO images for download instead of distributing them as physical discs (or at least provides the option to). And with the widespread use of netbooks (laptops that doesn’t normally come with DVD drives), you might find yourself still trying to find out how to use ISO images. Again, you can burn these files to physical drives (which you would probably still use another App) or just mount them using simple, widely available tools.