I was not a huge fan of Pottermore, but I cannot deny that I was delighted by the content that was added on there. I do wish that Jo had actually published that encyclopedia she promised!
Learning about other schools, and the backstories of some characters (like McGonagall's tragic love life) were some of my favorites. I really liked the 2014 Quidditch World Cup passages that Jo would post. It was like being part of the wizarding world LIVE.
I am a big fan of the original games though, although my favoritism probably ends with OOTP for PS2. Not a fan of the games after that. I think my favorite (and I keep saying it, without really thinking about it haha) had to be Prisoner of Azkaban. I just liked the overall content, though I have a soft spot for the Chamber of Secrets video game.
I should add: I will be reading the Tales of Beedle the Bard to my children one day, I guarantee it.