I drink a special kind of water - the brand is Del Cano
Tap water here is pretty great so that's what I do. I buy some bottled water at work, but it only costs me 21 cents a bottle (1.5 l) at the very cheap supermarket on our doorstep. That would be 33 cents in the States.
I'll drink water from the tap if it tastes good...water does have a taste, sometimes it is more noticeable than others. I think for people who are very sensitive to the taste of water and have the money to spend, I don't see why they shouldn't at least be helped by a water list that describes each one. A sommelier...that's taking it a little too far. Certain waters don't agree with people also, sensitive stomachs and all that.
I have friends living in London who tell me the tap water in certain areas gives them weird symptoms later, and also it tastes funny. So they don't drink tap water.
There's also the case of being poisoned by tap water, which has occurred ocasionally in some places (some toxic product being discharged into the water supply or water that hasn't been duly processed getting to taps in peoples' homes), but then I have also heard cases with tap water of a similar nature.
I think it's silly to pay ridiculous amounts of money for "special" water. I'm happy with tap water. But I also think that in the future we may have to pay to be able to obtain it...and that's a far more serious situation.