It is asked a lot, but the importance is in determining whether a crime counts as Moral Turpitude, and hence whether or not you can enter on the Visa Waiver Scheme. Theft is Moral Turpitude, so the VWS is not a legitimate option.
Though as others have said, there would appear to be little chance of problems occuring if you do seek to use the VWS.
p.s. I think you could need to speak to a solicitor specialising in US Visas to get a definitive answer on whether your record would mean the Embassy would not give you a visa. Exactly how the embassy arrive at a decision is not exactly published info. to my knowledge. The age of, nature, and number of crimes are taken into account.
pps. I suggest you read this bit of the US Foreign Affairs Manual here...
http://foia.state.gov/masterdocs/09fam/0940021 aN.pdf
... Interestingly I see it says crimes, *including* those involving Moral Turpitude do not render you ineligible for a visa, if they were committed prior to the age of 18.