It depends on what you intend to use it for. Distilled water is the purest and therefore the only option for chemistry experiments. Hydrating yourself with that will kill you, so it's not an option at all for that. Tap water is fine for cleaning and drinking, but I prefer slightly sparkling water as a refreshment.
@LeopoldBloom hmm, I looked it up and it turns out you're right. As long as you get enough minerals from food, it won't kill you. I've been lied to by my biology and chemistry teachers! 😯 It also doesn't offer any health benefits compared to tap water though, assuming that's safe to drink.
