Our daughter has been "sleeping through the night" since she was about 4 weeks old. I know how lucky we are, and I'm sure we'll pay for it somewhere else. At about 7 weeks old she switched to 12 hour nights, not every night but most of the time.
Last night my wife, myself and my daughter all slept the entire night with none of us waking up even once. That has never happened before. I don't think my wife and I have both slept through the entire night since before we were trying to get pregnant. At that time I started work at 3am, and when we met I worked nights, so I think its safe to say it was the first time even the two of us have actually slept all the way through the night.
It was awesome, and I didn't think the college kids at my job would sympathize with me. For the record My daughter is just a little over 5 months old.
Dave the J
Re: last night we all slept
Well, a lot of them are staying up until 2 am or later by choice, drinking, then rolling out of bed to come to work. So you're probably better rested than half of them!