Not counting iOS titles (there's actually been a LOT of great ones so far this year. Monster Flip, Coco Loco, Adventure Bar Story, Ragdoll Blaster 3, I'll stop...)
But so far I've actually only bought 2 video games this year. PokePark 2 and Devil Survivor 2. Both are a lot of fun, but for different reasons. But so far I would say based on the amount of fun I'm having, I have to give it to PokePark 2.
...I'm sure about 90% of the people reading this have already rolled their eyes and are choosing to ignore my opinion, but that's where I stand right now.
For other games I tend to buy this year, my game of the year will probably either be Lollipop Chainsaw, Bioshock: Infinite or Persona 4: Arena.