My favorite is the Elder Scrolls VI announcement trailer / teaser. It conveys everything what I would want in expectations. The lore and story looks amazing.
My favourite is the E3 CGI Assassin's Creed III trailer. I think they played into the fantasy of the American Revolution and defined Connor's character as well as they could within 4-5 minutes.
Not necessarily my fave, but I recently saw this Uncharted 4 commercial and was reminded how fantastic it is—completely sells the plot setup which I was a bit iffy on: