In my case it would be totally Dragon's Dogma, I've always been a fan of RPGs and DD had me hooked from start to finish, it's a real shame that people don't make mods for it anymore.
I think that Emergency 4 was a bit underated for what it was, no one exactly hated the game but it definately deserved more attention, it was a very accurate and fun way of becoming some sort of 911/999 operator and the modding community was pretty good as well. There were even military simulations mods you could have and they were alright as well.
I love the game DD, but I like to play it offline with friends most of all. I have an artist friend who is the author of all the quests and makes all the storylines for us, and due to her, the game is even more cool and interesting. Of the other games so far, I only play gratis spil, because before going to bed, I want to relax and play something not very difficult and tune in to sleep. By the way, I would like to know if there are any game developers here and if they need testers, I would be happy to test new games even before they come out in the apple store