Wow! Just look at the breadth of games on display as people's favorites here! Loving it.
The indie scene's become a big part of gaming for me, I'm not sure what my favorite title has been...

Minecraft.

I haven't played a heap but World of Goo and Bit Trip Runner are the two that stick out for me.

Limbo.

Valiant Hearts: The Great War
Loved this game.

Binding of Isaac.

Rebirth was just released, and it is amazing.

FTL, Hotline Miami

Special mention to Crypt of the Necrodancer and Paper Please for their inventiveness.

so hard to pick. bastion, to the moon and dont starve are amazing games, some of the best i ever played.

i love you. still havent played transistor but will certainly play it. bastion was amazing, fantastic graphics, art style, gameplay, story and story telling. it was amazing. 

Gotta be minecraft, so many hours sank into it on all platforms.