Sorry Chris - your answer is wrong, though the US London Embassy would have otherwise.
Their line is that whatever the crime, you should apply for a visa so that THEY can decide whether it is moral turpitude or not, and incidentally pocket $100 or what it is visa fee. They do not trust (probably correctly) Joe Public UK to have the faintest idea of what does and does not constitute moral turpitude.
But you ARE entitled to decide for yourself about your crime and there is plenty of guidance online.
http://en.wikipedia.org/wiki/Moral_turpitude for example.
If the crime is NOT moral turpitude then you can quite truthfully and legitimately tick the NO box on the visa waiver /ESTA form and need not apply for an unnecessary visa.