My current game of choice is the newly released Construction Simulator 3.
I also like Pro Series drag racing, Plague Inc, and Auralux 2.
I used to play a lot of Shadowgun Legends and The Sun: Origin, but they are not complete games. The storylines are not finished, and I got bored waiting for updates to wrap them up.
Dead Trigger 2 is fun, but gets boring after finishing the main story line.