Any examples from the early days of success stories such as Facebook, Google, Twitter, LinkedIn, Bebo etc would be good.
Having done both "normal" and "insane" hours I think the optimal is actually 40-50 hours/week but REALLY working productively during those hours (not goofing off) and spending the rest of time to rest and recharge so you can keep up 40-50 productive hours/week for 5+ years. Startups are marathons not sprints.
