Today I have to over my old work laptop that I have been using for my personal work and was little concerned whether anyone whom the device falls into hands of is able to recover my data.

I did a fresh delete of everything that I could think of but was still not satisfied. Here are a couple of posts that make me a happy man now.

http://hivelogic.com/articles/how-to-prepare-a-mac-for-sale/

http://www.tuaw.com/2010/09/24/mac-101-preparing-your-old-mac-for-sale-or-recycling/