As someone who grew up in Wisconsin where milk is served and drunk with every meal and even in between - I don't think there is such a thing as too much if it is not causing any kind of allergy or digestion problem.
We all drank alot of milk and to this day I have never had a broken bone which I probably should have and I have only had 1 cavity in my almost 34 years of life.
I think its great that he loves milk so much because it will keep him away from the other sugary drinks. I hope my son comes to like it as much.
I guess the only other thing I would say is that I know some doctors are suggesting that at 2 years old they switch from whole milk to a lower fat milk - but I would ask your Pediatrician about that.