The last one was definitely Mass Effect 2. I haven't played many new games over the last year couple of years, but that one definitely stands out. I liked Dragon Age quite a bit, but about two thirds in it I lost interest and lapsed out for a couple of months. I just found the story to be a bit bland and near the end it was dragging badly.
Much to my surprise, Cataclysm did not grip me as much as I thought it would. I find the whole "elemental upheaval" thing to feel trite compared to the Scourge in WotLK and Legion in BC. I'm also bored to death of Old Gods and Titans.