"In looking for people to hire, you look for three qualities: integrity, intelligence, and energy. And if they don't have the first, the other two will kill you."
— Warren Buffet
CEO, Berkshire Hathaway
My Buffet said it best IMHO... I've worked with some competent, hardworking, and passionate with no integrity who have really caused a lot of problems.
Being a non-technical co-founder, I did learn this the hard way a few times.
I totally agree that having a competent, hardworking and passionate programmer is probably the most important part of a startup.