As far as brand goes, it probably doesn't matter all that much. While the different brands surely differ a bit in their mineral makeup, they all contain the necessary yeast nutrients. Bottled spring or plain ol' drinking water is good, because you know it's bleach and microbe-free.
Likewise, if you think your tap water tastes good, go for it. It almost certainly contains the necessary ions as well. You may want to install a charcoal filter though, to remove any trace chlorine. Also, if you live in an area with lots of iron in your water, you might want to go for the bottled stuff.
RO water or distilled bottled water aren't too good to brew with. These water treatment methods both eliminate necessary yeast nutrients, which will ultimately lead to off flavors. It'll still ferment, but the lack of calcium, magnesium, and zinc (among others) will stress the yeast a bit.