John Stossel did some investigative reporting on bottled water last year for 20/20, including a blind taste test. I watched the report at the time, but the results are also still listed on the website:
http://abcnews.go.com/2020/Health/story?id=728070&page=1
The cheapest bottled water (American Fare, which is KMart's brand) came in first place, Aquafina was second, NYC tap water (from a public fountain in central park) tied for third with Iceland Spring, Poland Spring came next, and Evian came in last place, by a huge margin, with most people saying it was disgusting.
Personally, I think tap water tastes
better, but then again, it also depends on where you live, as I've visited cities that have terrible tasting tap water. But as long as I'm here, where the water tastes great (and I don't know why, maybe it's the flouride or whatever the hell else is in it), I'll stick with the tap water. The only thing bottled water really has going for it is convenience. Then again, you can always refill the bottles with tap water, if you want to carry them around.