The key to this list is books that have changed one's life.

In that spirit, apart from Gandhi's autobiography the other book that changed my life and millions of others is "Thirukkural" which was originally written in Tamil a few thousand years back. I don't have a specific English translation to recommend but here is one (from a wikipedia reference entry actually),

http://www.geocities.com/nvashraf/kur-eng/close01.htm