Although overdoing it may be necessary to meet deadlines.
No deadline is worth your health.And, one thing I noticed while working at Gremlin/Infogrames - the people from 'upstairs' who tell you to work overtime, always disappear at 5:30pm on the dot.
If they aren't prepared to do it, it isn't right that they expect everybody else to. I used to start at 9:30am (sometimes 7am) and I don't recall ever being home before 11:30pm.