I can't pick just one genre, I'm afraid, so I'll go for three.
For shooters, it's Spec Ops: The Line. A shooter that isn't just "USA R THE GREETEST" and that actually takes a thoughtful, interesting look at the horrors of war, PTSD, the relationship between the player and the player character, and critiques the entire modern warfare subgenre? Yes please! It's the first AAA holistic game, where everything fits the mood and the tone it's trying to create. Even the shooting, which would feel clunky and outdated in any other shooter, is here purposefully made to be that way to give the player the feeling that something isn't right, and that is an absolute work of genius.
For fighters, it's Blazblue: Contiuum Shift Extend. Great fighting, good story, amazing music, and some of the best characters in gaming. Makoto and Arakune are easily some of my all time favourite characters. Also, it's got a lot of funny extra segments, some tearjerkers, and a few really disturbing scenes. Seriously, one of them is a character essentially being mentally raped, I couldn't watch it. Scarring as that is, it's certainly a testament to the writing that they can make me feel so creeped out by it, and the villans are so evil that they're really fun to hate on and beat the crap out of.
For RPGs, it's Mass Effect 2. Honestly, it may be my favourite game of all time. The music is amazing, the characters really do feel like real people, the gameplay is flawed but fun, and the story is pretty good too. And the suicide mission is, IMO, the best final mission in gaming history. The music, the tone, the stakes, the choices you have to make, it's amazing. Ok, there's planet scanning, but I can overlook that when everything else is so good. I still remember that krogan poet trying to get his asari girlfreind to like him again. I hooked them up. If a Mass Effect game came out with 3's gameplay, 2's music and writing, and an upgraded version of 1's planetary exploration, it would be the perfect game.
