Plenty of people don't believe in free-will; in fact as computer scientists, many times with interests in AI, I'd suspect the majority of us are complete mechanists.
Free will has always been a very disputed notion since the Greeks, but the debate took another dimension with Freud's discover of subcounscious. As I said in my conclusion, I did not intend to open such a vaste debate here, I just noticed the paradox of Mr Buffet stance on this matter considering the core values of the society in wich he lives (and what he represents).
Yeah... while I don't believe in free-will, belief in fate is not a life philosophy. It's the kind of thing you want to ignore and pretend doesn't actually exist because it is not a happy conclusion.