BlazBlue and Red Faction: Guerilla. BlazBlue is certainly the better of the two; its one of the best games I've played in a while. RF, on the other hand, is fairly meh- its good, but it has very little plot.
I recently got around to playing Assassin's Creed (I've had for several months, but just never had time to play it). I wish I had played it earlier. I liked it. It was an interesting take on the open-world genre, except that it was good (technically Oblivion and FO3 were open-world too, but they were RPGs so I don't group them with GTA, etc.). The storyline made very little sense on the whole; the ending was very much a surprise, as it really had absolutely nothing to do with the rest of the game. I recommend it, though.