We have a big Britta filter in the kitchen. Makes more sense than buying bottled all the time (and all that plastic-ugh). I always carry a stainless steel beverage holder when I go out, filled with water, as restaurants here won't serve tap water. In the summer I'll have to switch to my backpacking water holder!
As far as I'm aware the inside surface of a "plastic" bottle or "aluminium" can etc is coated with some material, so you're never drinking from a plastic etc. Correct me if I'm wrong.