Fiberglass ... I don't know how I feel about fiberglass. Well, really, I do know, but do I feel that strongly about it to quadruple the amount of money I would spend on a tub? It doesn't look too bad installed with some tile. Or if it's a model that comes with a cover.
Of course, the wooden tub is traditional. But for some reason I think it looks geeky, too. Enough people are willing to pay good money for one of these things that I think I might be in the minority.
The outdoor stone pool is obviously ideal but the idea of replicating it inside strikes me as hysterical.