There are two parts to the wizarding world of Harry Potter at Universal Studios.
Hogsmeade
We visited Hogsmeade village on our way to the Hogwarts Castle and it was amazing!
Diagon Alley
Diagon Alley was everything I had hoped it would be. The dragon on top of Gringotts was amazing! You could feel it breathing fire!
Butter Beer
Don't forget to get a butterbeer while you are there. They are absolutely delicious!