i use a marc by marc jacobs tote. you know, the ones that he sells in his m by mj stores that say "jacobs by marc jacobs for marc by marc jacobs in collaboration with marc jacobs for marc by marc jacobs"
I love how many times i says his name. hahaha.
just big enought o carry towel, water, ipod, keys, sunglasses, headband. i dont like showering at the gym, so i never pack extra clothes.