I use an Eddie bauer diaper bag, so it looks like a gym bag, but has all the pockets and waterproof interior
http://www.jcpenney.com/dotcom/baby/clothing/categories/baby-gear/eddie-bauer-diaper-bag/prod.jump?ppId=1951db8&cm_mmc=ShoppingFeed-_-GooglePLA-_-Baby-_-1951db8&ci_src=17588969&ci_sku=1951db8