As if you needed another reason to backup your important data such as years of family photos, videos, digital works of art, or other irreplaceable files, this will serve as another reminder. I visited the Genius Bar at my local Apple Store this evening and while waiting I witnessed the desperation of a woman whose hard drive failed on her MacBook Pro. The young man at the Genius Bar said they would replace the hard drive for $132, but they had to take the old hard drive, and they would not do any data recovery on it. The woman was in shock and lamented the fact that if she were to let the Apple Store replace her hard drive, she would lose all her files and Apple would not give her the opportunity to try to recover the data on the failed drive.
It is apparently Apple's policy to not attempt any data recovery on any failed drives, likely due to liability and privacy concerns. Feeling bad for the woman, and knowing that I might be able to salvage her data using some data recovery tools, I offered to try to recover her files myself (I'm a consumer IT moonlighter in addition to my day job working in IT for a large corporation). I stated that I would not charge her if I was unable to retrieve any data from her failed hard drive. Due to logistics with her travel, she needed to get her MacBook Pro running immediately and so she chose to have Apple replace the hard drive and lost all data from her old hard drive.
Whether you choose Backblaze, Carbonite, CrashPlan, Dropbox, Live Mesh, Mozy, SpiderOak, SugarSync (my personal favorite), Wuala, or one of the hundreds of other online backup/sync services out there, having a backup will save you in cases such as this where your data is damaged, irretrievable, or stolen. Be safe!