I live in a pretty humid climate. Anytime I carry around a bottle of soda, or some cold water, the outside of the bottle gets covered in condensated water, that drips and gets water everywhere. I'm looking for a good waterbottle that's not too big, but has some kind of insulation or something else to capture/eliminate the condensation. Any one know of such a thing?

I'd like to be able to carry the bottle in my backpack with me, so it is always there, instead of only when I don't have anything else in my hands.