JoJo, easily. I was going in with relatively low expectations, with a relatively low profile studio being in charge and not liking the first glimpses of the anime designs. But by God, was I blown away. They did an absolutely stellar job with the budget they had available and managed to capture the essence of the manga perfectly.
Close second is Nichibros. Because it was funny. Very funny.

Jojo for sure. If nothing else, the OP is probably the first palatable CGI to ever come out of Japan.