I just bought another Skip Hop bag to use for our upcoming vacation and they are so handy, I go the Dash this time I've tried othersin their line but needed seomthing bigger. They are on sale all over the web right now in various colors for only $30.
Holds a ton, I have in it right now 4 diapers, 1 huggies 32ct pack of wipes, 1 pk Boogie Wipes, 3 ziplocs for any accidents, tube of sunscreen, 1 bottle, pack of liners, extra bottle cap, (there are inside and outside bottle pockets) sippy in an outside pocket, hand lotion, wallet, coupon pack, changing pad, 1st aid kit, a baggie of snacks for each child, antibactrial gel & spray for hands, cell phone in an outside pocket, digital camera & Flip in front pockets, this is everything that I took out of town with us over the weekend & I'd take to the parks for a 1/2 day as well.
It will hook on the stroller and have a longer carrying strap. I'm not a back pack fan but can wear the bag messenger style across my shoulder to my opposite hip very comfortably. I had my youngest's name stitched on the front for a nonminal fee locally and it turned out super cute.