Before SO it was google groups/dejanews for me. I suppose it does make us a little lazier, but I don't ever take the answers on SO as fact. I always try them out and usually end up changing them around to fit my specific situation.
This can be applied to any site that offers value. Before Stack Overflow, it was whether Google was making you dumber. In my specific case, no, SO has not made me dumber. I've learnt heck of a lot from that site.