I guess I'll be the first to say Assassin's Creed 2, the first game had a great premise and featured an intriguing cliffhanger ending. Yet the game was marred with bad and repetitive design, so I wasn't sure how I was going to stomach the sequel my friends insisted I play and well hot damn if it was absolutely better in every category and actually made good on the promises of the idea. Its still my favorite new IP from this generation.

Threads of Fate and Evil Zone are two other games I ended up greatly enjoying despite not thinking much of either when I saw screenshots and read descriptions.