I really appreciated what Kristen, The Frugal Girl, had to say today about bottled water consumption...the wastefulness of all those plastic bottles, so many of which are not recycled, and that bottled water is often worse in purity than tap water.
I also think it is important for us to present a solution when we address an issue like this, and filtering your own water is one of the very simplest things you can do! She mentioned making gradual changes if you are in the habit of using bottled water on a regular basis. If you can commit to even decreasing your bottled water consumption (rather than eliminating cold turkey) this is a step in the right direction.
Check out her post on bottled water.