There really isn't a best box..it's what you would like and would be happy to display in your bakery.
I personally liked the Cauldron and Bucket of Treats. I wanted the Mummy Family ever since I saw one of the players posted on the forum..got it on the 9th try! I didn't get the Candy Apple Display from the Bucket of Treats after 4 tries, but got the Candy Exchange so I'm quite happy with my prizes.