If we take the games out, I'd say @steemhunt is the objective best DAPP contributing to the STEEM blockchain. It's got so many great features that are ahead of competition. It's one of those rare times where the clone of a project (Product Hunt in this case) is far superior to the original.
Promoted polls are listed on our promoted page. Additionaly, the highest amount spent on a poll between active polls gives a winner spot on the homepage.