Lots of these games are overrated in my eyes.
Batman: Arkham City - I got bored pretty quickly. Never finished.
Bioshock - Was super pumped about this game and it did not disappoint!
Grand Theft Auto 4 - Hated it almost from the get go.
Grand Theft Auto 5 - Better than IV, but still got bored. I've just never "got" this series.
The Last of Us - Enjoyed what I played, but never finished. Will buy again on PS4 and finish it then.
The Legend of Zelda: Twilight Princess - Played the crap out of it for about a week and then just stopped. Plan on playing it again SOMEDAY.
LittleBigPlanet - Very charming, but couldn't hold my attention. Part 2 was a little more robust, but still couldn't get into it.
Mass Effect 2 - Never finished the first one, but really enjoyed part 2 even though I didn't have a save file to carry over. Still have Part 3 sitting unopened on the shelf.
The Orange Box - Played through Portal and HATED it. It's still on my shelf to come back to for Half Life 2 someday.
Portal 2 - Only game on the list I haven't played. Never will. See "The Orange Box" entry.
Red Dead Redemption - Same as GTA. Just can't get into it.
Skyrim - Put about 50 hours into it, but just got burnt out. The only Elder Scrolls game that's held my attention past the first couple of hours.
Super Mario Galaxy - Loved it!
Super Mario Galaxy 2 - Haven't finished. Waiting for the right time. I tried playing it right after the first one. Too much Mario.
Uncharted 2 - The only one in the series I've played and I loved it! Someday I'll get around to playing 3.
I don't know why I felt the need to type all of that out. Looking over it, I guess I just don't like the Rockstar style.