What video game should I get?

I have an xbox 360 (I'm hoping to get another system soon) and I play games like Left for Dead, Wolfenstein: The New Order, Condemned: Criminal Origins, Borderlands 2, GTA(I have had almost every one), sometimes I'll play Black Ops 2, The Walking Dead: Survival Instinct, and Halo 2 and Halo Reach.
I have The Sims 3 and Minecraft as well but rarely play those, they're mainly games I have for my younger siblings.
Any suggestions on a decent game to get? I'm looking into getting a new video game as I've basically beat almost every one I have and I want to get something new to play.

Have you tried Assassin's Creed? I like that one, Brotherhood is one of my favorites. I've also got Assassin's Creed 3, and Black Flag. Black Flag is another favorite

Have you ever tried Skyrim? Skyrim is a fantastic open world RPG for the Xbox 360.

Tetris