Personally, I don't think it's stupid, but I do think that we [meaning American society] have become self-indulgent in our throw-away mentality when it comes to bottled water. Here's a very interesting [also very long] article on the subject at Fast Company.

Some things to think about [quoted from the article]...

• Last year, we spent more on Poland Spring, Fiji Water, Evian, Aquafina, and Dasani than we spent on iPods or movie tickets--$15 billion.
• We're moving 1 billion bottles of water around a week in ships, trains, and trucks in the United States alone. That's a weekly convoy equivalent to 37,800 18-wheelers delivering water.
• One out of six people in the world has no dependable, safe drinking water.
• In Fiji, a state-of-the-art factory spins out more than a million bottles a day of the hippest bottled water on the U.S. market today, while more than half the people in Fiji do not have safe, reliable drinking water.
• We drink more bottled water than milk, or coffee, or beer.
• Tap water in this country [U.S.], with rare exceptions, is impressively safe. It is monitored constantly, and the test results made public.
• In blind taste tests, with waters at equal temperatures, presented in identical glasses, ordinary people can rarely distinguish between tap water, springwater, and luxury waters.
• Bottled water is dominated in the United States and worldwide by four huge companies. Pepsi (NYSE:PEP) has the nation's number-one-selling bottled water, Aquafina, with 13% of the market. Coke's (NYSE:KO) Dasani is number two, with 11% of the market. Both are simply purified municipal water--so 24% of the bottled water we buy is tap water repackaged by Coke and Pepsi for our convenience.
• The Fiji Water plant is a state-of-the-art facility that runs 24 hours a day. That means it requires an uninterrupted supply of electricity--something the local utility structure cannot support. So the factory supplies its own electricity, with three big generators running on diesel fuel. The water may come from "one of the last pristine ecosystems on earth," as some of the labels say, but out back of the bottling plant is a less pristine ecosystem veiled with a diesel haze.
• Water bottles are made of totally recyclable polyethylene terephthalate (PET) plastic, so we share responsibility for their impact: Our recycling rate for PET is only 23%, which means we pitch into landfills 38 billion water bottles a year--more than $1 billion worth of plastic.

Although it's a long article, it presents arguments from both sides of the house [unlike my opinionated excerpts above] and gives some validation to the business of bottled water. For example, bottled water is a purchasing choice and if people were buying soft drinks instead then the 38 billion water bottles would still be going into landfills every year, but labeled "soda" bottles.

I'd be a hypocrite if I yelled from the roof tops a whole bunch of negativity about bottled water. I have bought it and will continue to do so, but rarely. Most of the time I use my own [sometimes filtered] tap water in reusable bottles whenever I can. I know people who buy cases of bottled water to drink at home and I just don't get it....

24% of the bottled water we buy is tap water repackaged.

~tod