Well, it often leads both ways. With Ed Witten, physics has led to new math and a Fields medal for him. And the other way, Galois and group theory has led to all sorts of goodies in physics with gauge theory etc. I had voted to close, but am now apologizing :) Recently, [Andrew Hodges](http://www.twistordiagrams.org.uk/), an Oxford mathematician and writer of an excellent biography of Alan Turing, called [Enigma](http://www.amazon.ca/Alan-Turing-Enigma-Andrew-Hodges/dp/0099116413) wrote a paper with Nima Arkani-Hamed--[Twistors](http://www.twistordiagrams.org.uk/papers/index.html), and Alain Connes, another Fields medal mathematician, has been using [non-commutative geometry](http://www.alainconnes.org/docs/einsymp.pdf) for interesting speculations on physics (even if he has admitted problems with the theory---great man.)
Then, there is Mad [Max Tegmark and his theory that all mathematical stuctures have a physical reality](http://arxiv.org/abs/0704.0646) which is the ultimate in Platonism :)