I'm pretty much drinking only bottled water now since apparently our tap water can cause cancer.
I've heard that testing outside of the U.S has proven that the plastic in bottled water can cause cancer to. And considering there are more regulations put on tap water than the bottled stuff, I'd say tap is pretty okay. But than again, I dunno, is there something weird being put into your local water supply? If so, that's pretty scary.
OT: Root Beer, yum!