I like the polls feature very much! I use it over in the Creature Catalog forum to get feedback on conversions and original mosters. It helps keep thread lengths down by just having people cast a vote in a poll instead of having to make a reply just to say yes or no--but I have to be sure to provide responsible and intelligent options for them to chose from. And, if they have a specific critique, then they can go on and post a reply. Used properly, the polls can be a great benefit to the forums.
But I also agree that things can get out of control. In that instance is incumbent upon moderators and administrators to prune out polls that are just tests, that are off-topic, or that are just plain silly. We have the authorization to delete posts and polls for that very reason.
And I also agree that when the novelty wears off, the polls will decrease.