Apparently, in the new comic they're upping Superman's heat-vision power to something they're calling "Super Flare". He can take out a city block (why would he want to?), but it depletes him of power for about a day. Maybe Kryptonite was getting passe.
The article I read on
DC Comics Blog had a cool picture though that tells when Superman got his powers.
Maybe it just kicks in when you're over 75. /ducking/