This is like a really weird gunslinger duel situation. While Toph has to perform martial art and can't simply think about it, therefore loses first draw, her ability execution is faster and more versatile than Magneto. Magneto could simply lock Toph in position while Toph could wrap the metal around his head to blind. It kind of boils down to who can use the metal of the other person to defeat them first. It's a contest of initiative. It would be really interesting to see a match between them with the rule that they can't affect each other.
Of course, if Toph didn't wear metal, she would totally kick her ass.
THIS. IS. GLORIOUS! And they definitely match up very well it terms of abilities. Could Magneto catch metal faster than Toph could hurtle it? Would Toph be skilled enough to find a way past Magneto's electromagnetic shield? I'd say..I'm giving a VERY VERY SLIGHT edge to Toph because she can manipulate the Earth and unless it has a very high metal content, I'm not sure if Magneto can slow a boulder's velocity properly. Then again I've not read every comic book he's ever fought in so maybe he has done that before. That is of course if he doesn't simply reach out and shake her around by her armor as soon as the fight begins, squeezing her to death ala Sith Lord style for the entire body. God damn, maybe they ARE evenly matched! THIS IS BEAUTIFUL!
Ooh another factor that could have a major impact on the fight! How good is Toph's hearing? When Magneto makes a magnetic shield for himself would she hear it crackling like ive seen it in comics? Or would Magneto be able to rain death from above? Move and counter move! I want to see this as a real Death Battle!