Good mic for gopro 3?

im looking into upgrading my first hero to the new hero 3, my friends and i used it alot last year and i think it would be worth the investment into a new one along with a mic setup. just for attaching to a ski pole and do follow cams and some other shots like that. nothing too too serious i just feel that good crisp audio makes footage that much better. also looking at the polar pro polarize filter and the mic that they make but its discontinued on the site and B&H. any help thatd be great!