No, milk allergy, I presume, because he said milk allergy. Lactose intolerant is completely different, and most people "grow out" of lactose intolerance around the age of 10/11. I used to be lactose intolerant.

Anyway, it really all depends. Soft serve I always go for "twist", or whatever each individual place calls it, 1/2 vanilla and 1/2 chocolate. When eating "regular" ice cream, I usually go with vanilla with a shitload of chocolate syrup, and I think that tastes better than plain chocolate ice cream. If I didn't have access to syrup...I don't know which way I'd go.