While I have noticed some very good replys. Lost of people mention zero'ing out the drive is sufficient. I know somone that claims to have an app that will restore a drive zero'ed out up to 8 times over. I have never seen this in operation, but he claims to have restored crashed drives with the application to get them up long enought xfer data. *Shrugs* could be a lie, who knows.....
Also,
I had to take a client's think-pad HD to data recovery specialest to recover some time sensitive unique data. The place that I took it to prided theirselves on their recovery succcess rate and had some pictures of various drives where data had been recovered. Among these included Hard Drives damaged in Fires and Floods. They were good. They recovered everything from a Laptop drive for me that was no longer recognized by the computer. Yes, they were expensive. But just know that some people are willing to pay the price. When you add curiosity to the factor, you have to ask yourself how much one would pay for a key to open a chest of unknown contents.