Bottled water is not only absurdly overpriced for something we already pay for at home, but it's not very environmentally friendly, nor is it really any safer than tap water in most cities. There is a lot of waste and cost associated with the production and transport of bottled water. Take a look at the video below, The Story of Bottled Water, for an eye opening look at the evolution of and waste created by the bottled water boom.
I am by no means perfect, and occasionally will consume bottled water when I have no other option, but I make every attempt to recycle that bottle even if I have to bring it home to do it. We have a reverse osmosis filter at home, which we use to refill our water bottles and make water for the fish tank, but I am appalled at the amount of water waste it produces. I wish we lived in a house so we could have a way to catch the waste water and use it to water the plants and such.
For more information, check out the articles at http://planetgreen.discovery.com/bottled-water/
If you need your own reusable bottle, here are some options: