There are two games that I have spent a considerable amount of my life playing Planetside 2 and Path of Exile.
Planetside 2 released it was exactly the game that I was looking for. The experience of playing in an organised outfit was the best multiplayer gaming I've ever experienced.
Path of Exile is like a sledgehammer of a learning curve. Never had played an ARPG before this but once I got to maps my soul was taken indeed.
Before this left4dead 2 was the game that I had suck many hours into - what a game!