Thanks for this interesting question as my answer has a long story behind it. However, I'll try to keep it as brief as possible.
The short answer is, I drink tap water. which in our area is filtered for approximately 15 years through chalk, as we live on top of a massive artesian well. I also grow a number of herbs which I occasionally brew for a change and little taste, but I actually prefer the taste of the pure water. I have tasted water from other areas around the country and around the world, but I do not think that I would be able to have the same liking for any water that is not to my taste.
The longer answer involves explaining that I first started drinking water because any drinks containing caffeine (tea/coffe etc) used to make me shake in the manner of Parkinson's disease. Plus, sugary drinks and alcohol have also been off my menu for many years.
What I found was that drinking seemed to be habit forming, so whatever it was I drank became a routine. With a bit of self-analysis, I came to the conclusion that I actually liked the water more than any of the other drinks on offer.
The moral/lesson (if there is one), would be to drink what you like drinking, and the only way to find that out is to try as many things as you can and take note of what you like and what is suitable for you and your health.