2 for sure.
First one, although really good story, in the other departments wasn't anything too special sonce it had to lay the foundation for the series. Almost no variety for the side missions(basically the same three or four types of missions over and over again), Cole's character was rather bland, and the melee left a lot to be desired. The game is amazing, but it's the little things that put it behind 2 for me. 2 on the other hand fixed all of these by making Cole's personality more dynamic,. giving him an the Amp for melle combat, more variety to side missions, user generated missions and the addition of ice and/or fire powers to go alngside Cole's electric powers. Also, although the ending to 1 was amazing with that twist, whether you chose to be a hero or infamous, it didn't really change much. While in 2, the endings are vastly different and the infamous ending in particular was very emotional for me since I got attached to certain characters...
Second Son, in terms of gameplay and freedom is the best, but Delsin is not that great of a character and the story is rather forgettable too. Main villain is also nothing special compared to the previous two. First Light, thanks to Fetch being a pretty interesting character and the way we find out about her past made me enjoy it more than Second Son and also Neon is best power ^^ I love the series as a whole though, all the games are amazing(got all 4 platinums).
I guess for me it would be:
1. InFamous 2
2.InFamous
3.InFamous First Light
4.InFamous Second Son
