We can all agree it would be an awesome fight. But to be fair you have to look at the pros and cons of each side. Starting with Ironman. First major flaw, no suit means no skill. If bats found a way to power down the suit it would be over. But on the flip side Batman doesn't have powers at all. Both of these men are brilliant in their own way but one is a better fighter than the other..... Batman. If you want to get really nerdy about it all the B-man needs is an EMP grenade and he's set. Only a few of Stark's suits can with stand an EMP. So Batman would win.
Batman would win (eventually) because he would figure out a way to turn Ironman into a wanted villain by goading arrogant Tony Stark into doing something that every government in the world would hate him for. And I don't care who you are, one vs. the world always ends with the world winning.
Or maybe Ironman would just beat Batman to a pulp first, but Batman would die a martyr while Ironman would e an infamous villain. Oddly enough, my spellcheck recognizes "Batman" as a word but rejects "Ironman."
ya...this is not a hard decision. iron man would just shoot a few missles at him and kill him. besides, its not like any of batmans powers would go through that armor iron man has.