Honestly? The Elder Scrolls V: Skyrim.

The soundtrack soothes me and I loose myself in the world of Tamriel. I find new things every time I play, even after playing for over a thousand hours. Oblivion was good also, but I connected better with the harsh, wintry climate of the North, war torn lands and dragons. There's still so much more I need to do and discover so much every time.

The Witcher 3 is very close to my heart as well, but not as much. Spent nearly three hundred hours lost in that world. Still need to get on to Blood and Wine.