Personally I don't think people down vote enough, I see way to many answers that are just plain wrong or mis-informed that don't get down voted and leave bad advice or suggestions that someone that is new won't know is bad advice or suggestion. And there will be people with 10K or more reputation that post answers and still don't down vote the empirically bad answers.
I up vote the answers that are most importantly correct, and then well thought out and detailed. But I feel I am the only critic some times down voting all the wrong answers that don't even address the question at hand because someone answered without reading for comprehension. C# answers on Java questions, and vice versa are good examples.
What does meta think?