Wouldn't it make sense to have a badge for questions (or answers) that continue to be useful long after they are posted.
This would be questions that receive something like 500 views/week for 8 months, or 2 up-votes per week for 6 months. This would target questions that are general, useful posts that continue to contribute to the community for a long time.
One of the main purposes of the Stack Exchange sites is that Q/A posts will serve as a sort of wiki after the question has been asked and an answer has been accepted. This badge would encourage people to ask useful and general questions that will continue to help Googlers and the general public.