I'd rather have a brand new Zelda title before either remake. But between the two games, I have to go with
MM because it's one of my all time favourite Zelda titles and it holds a lot of nostalgic value for me. Don't get me wrong though,
ALTTP is my favourite top down Zelda.
I just figure it would make sense to do
MM, since it takes place directly after
OoT, which is on 3DS. So the new generation of Zelda gamers can play through the next piece of the hero of time's story without having to get another gaming system involved. Also it would be such a dick move if Nintendo totally ignored "Operation Moonfall".