It all depends on how much time Batman and Iron Man have had to prepare. If they've had time, this could be an epic battle. If not, then Iron Man wins pretty easily. But, both have the power of preparation. I know that many of you only go on the movies, and only see Stark's power is the suit. Actually, its preparation and forethought. He has thousands of suits, many tweaked for specific battles. During the AvX event, he had one suit to fight Magneto (he won) then another to fight the Phoenix (a god like entity that planned on scouring Earth of life) and yet another for stealth, and even one more for fighting the Phoenix 5. So, if Bruce and Tony get to study one another for a time period before the fight, oh, its on.