Batman all the way. Lol, Its funny I was just teasing one my friends, a big Ryu fan, about how Batman would whip Ryu's ass. He then proceeded to elaborate on how Ryu can harness and use his Ki not only internally but externally as a destructive force and how Batman can do neither, thus putting Ryu on a far higher plateau when it comes to martial arts. I conceded the argument, and instead brought up Iron fist, and he never even heard of the guy so I'm going to be completely bias for the sake of making his awesomeness more well known, and go with Iron Fist, just because I think Ryu is a bitch.
I think it would be interesting to see a fight between Kenshiro and Ryu, though I think Kenshiro would win, bias aside.
In a fair fight, Ryu all the way. He has been training all his life and Iron Fist has only been training since he was in his 20's. But a full power Iron Fist has too much under his sleeves, with the power of Kun'Lun and all. Ryu would put up a good fight, but Iron Fist is just a bit too much for him. Though if this was Iron Fist of the 80's, yeah, Ryu would kick his ass. Powerman too I think. Though I doubt he'd be able to walk away afterward if he fought Powerman.
Ryu is a pansy video game cross over character and iron fist has been kicking better quality arse for a lot longer, that and he's got a seventies style costume and a big freaking tat and does not look like the karate kid on roids.
I officially, after 20 odd mins of internal debate cannot answer this question... haha, seriously, most either/or q's I can answer instantly, well done for stumping me and adding yet another unanswerable universal question to the pile!
I could always amke a Mugen Iron Fist and pit him against the hardest version of RYU!!! Hmmmmm... gonna go see how much work that would be?