Callista,
Calista,
Kallisto, Kallista are all nice names for girls/women IMO.
Kallisto is the most "out there," but it isn't unusable.
Callisto seems gender ambiguous to me. Kalista looks wrong and trendy to me.
I think I like
Calista best. It looks more airy and elegant and neat than
Callista. If I wanted it to be a mythology name, and not just a pretty name I liked, I'd use
Kallisto.
- mirfak