Wow I have to say, that is a poor attitude to take considering the climate change problem we are all going to be facing soon enough - which is pretty universally accepted as the truth now. Put it this way, my total saving plans come to 5.82% (and growing) for the school which works out at 1.15MWh - which is ~5000kg of carbon dioxide being released needlessly if we don't reduce that cost. That is a huge amount of energy, costing a large chunk of money. (About £1300 a year IIRC). Surely £1300 of equipment won't break outside warranty because of switching on and off?
All computers, everything, here stays on 24/7, term time.
We use the EZ GPO addon so things go into standby mode if not used, but turning things on/off every day is not worth the problems we have had in the past with PCs deciding not to boot up one day for no reason.
Any possible saving in power will be outweighed by repair/replacement costs of equipment dying. So In my view, its not worth it, economically speaking.