I think 4e. I recall all the Dragon articles leading up to 3e and was not sold until it came out and then I was onboard and thought it was great. 4e had a lot leading up to it and I found myself leaning in to it more during pre-launch. It was different, but was able to DM easily and I am a fan of rolling spells to hit, even with things like fireball where you roll to hit reflex over having the DM make the roll to save. (I just let my player roll the save, but not as fun/cool)