My VW golf has a large enough holder in the door for a 1L nalgene bottle. It's AMAZING. I rarely drink from it while driving but I often take a large bottle of water with me wherever I'm going, just so I have it to drink from at my destination, or whatever. For example, each of the past 2 weekends I've driven an hour each way to a trail race and have lots of water when I arrive. I suppose I could just let it bang around in the trunk the entire journey, but having it secured seems far more civilized.