I know that LinkedIn culturally didn't work crazy hours to get where they were - does anyone know, are any others listed that started out as '9-5' organizations?
I am skeptical of the 60-80 hours thing. It seems like more of a macho thing than a real requirement. The problem is that when you workaholic yourself your productivity per unit time drops, so you're spending more hours but doing as much as you might do in shorter bursts of more focused time. In some cases it's worse... you get total burnout.
The 60-80 hours thing is how computer peeps express their machismo. If we were jocks, we would do like 1000 pushups or something. If you need to spend that much time getting it off the ground, you are doing it wrong.
I see more value in accomplishing stuff in as little hours as possible. It's not about the hours, it's about what you get done.
And once you get stuck, it can be more productive to leave the computer and get some sleep, eat, walk, take a shower, etc. The best ideas or solutions come to you when you're doing something else.
To me, saying you work 60-80 hours means you're either doing something very simple, or you're not doing much at all.