We have some small mason jars, used for jarring jam or jelly, that are perfect for toddlers to drink from. They come with lids, too, so you can throw one in your backpack and hit the road. This has worked well for us, except of course in the car, because it will spill everywhere. A major plus is that it has multiple uses so it won’t end up in a landfill, and won’t leech any nasty chemcials in your sweet baby’s system. You can get jars at a local hardware store.
The new Born Free cups are working well. My 7 month old is able to use it with help and my toddler likes it too, although she soaked her car seat by dripping water from the spout. Oh well! The cups are not completely drip free, but I’ll take it since they can go in the dishwasher AND have no BPA (see post below for a description of the chemical BPA).