If you don't have a current PC, you might find some games that are Xbox One/PC exclusive currently, like Rise of the Tomb Raider or Gears of War).
Other than that, Dead Rising 3? Quantum Break? I know it's lampooned, but I've heard Ryse: Son of Rome isn't bad if you get it cheap from a friend of Mine.
For me, my xbox one has been a Just Cause 2 machine, mostly because I bought just cause 3 and it came with a copy of Just Cause 2 for free.
Otherwise, if you wont be getting 3rd party multiplat games for it and Halo is a "no", you might find it's a Rare Replay machine for you, personally.