It's corn. I've experimented by mixing the Poor Richard's Ale (~20% corn) 1:4 with my Church of Chocolate Brown. I think I'll add corn to the next batch.
Cream really refers to mouthfeel and sweetness. Corn, MD and lactose all work. Corn can't be used in extract recipes and is tough to convert completly even in mini-mashes.
Now this is a rather personal question, don't you think....?
I am makking a stout and it does call for Lactose. I have MD as well, but I used it in my last batch of beer so I wanted to see what the difference would be in taste. Although I dont have enough expereince with the two to probably know the diffeernce with regards to taste.