My friend put either the Sobe Lifewater or Vitamin Water stuff in his bong once...it was a dark red/purple flavor which I assume was Raspberry or Pomegranate. It was pretty good, but we had some tasty weed in there too. I bet if you put reggos in there it'd be gross.

You're probably best off sticking with water. Most of the flavored stuff tastes good for a few hits but then gets gross, and can get your bong sticky and full of gunk.