Many people to whom I have demo'ed, have said that I have a good idea. I also have an almost beta, prototype.
I have approached 16 potential cofounders since May 2006, but they didnt want to take risks with their career, had families to support, had their own career track to pursue and frankly, wondered how it would make money.
Not that you should start a company with a stranger, though; I would not recommend that.