Gears of War, Assassin's Creed and GTA4.
I thought the premise behind GoW was dull, uninspired and overly derivative. I also found the combat too simplistic and unrewarding. I could respect the quality of the product, particularly its presentation, but I just couldn't enjoy it.
I won't say I didn't enjoy Assassin's Creed... but I grew bored of it far too quickly. There's simply not enough to do outside of the main storyline. In a game where plot progression revolves around completing the same objectives over and over, the lack of alternative activities and points of interest is painfully noticeable. Don't start on with the 'but you can collect flags, explore the cities and complete all the secondary objectives too' rubbish. We all know that collecting flags is boring, that despite being fairly vast and expansive, the cities really have nothing to do in them other than free-running, and that the optional objectives were the only part of the game more repetitive than the plot objectives. Despite that, I still have a huge amount of respect for it as a game. The execution and animations of the free-running element are simply perfect. The game's presentation is amazing too, and I still consider it to be the best looking game on any console to date. On top of that, Altair's appearance has to be the most well designed of any protagonist in any game. It's simply badass.
As for GTA4, I wanted to love it, but I just didn't. It's not that I didn't enjoy it, it's just that I didn't enjoy it near as much as I was expecting to. I don't know if it's because I've grown out of the franchise, but I doubt it. I probably would've enjoyed it a lot more than I did if it didn't drop frames so damn often. If I buy a console game, I expect the framerate to be consistently smooth. It's a small factor when you consider the game as a whole, but it really shit me up the wall. Apart from that, I didn't particularly like the character of Nico or the 'fresh off the boat in the promised land' flavour of the story. It just didn't do it for me. That being said, there were a whole lot of things to like about GTAIV, and I still consider it a very good game.