I only drink carbonated, filtered water that I carbonate myself.
I used to drink only Perrier, but that got way too expensive, though it's still the best ever! I used to drink diet soda with no caffeine, but to make the doctors quit bitching at me, I switched & found I actually I prefer the non flavor of a seltzer style.
I have always had trouble drinking plain water, it sits like lead in my gut & I can't ever drink much of it. I've been that way my whole life & don't know what the reason is for it, but it's not "in my head".
I cannot tolerate drinking sweet drinks other than maybe a little orange juice, maybe, but I have to wash it down with something not sweet.