X.O.
For me personally, Grace. Elowen sounds rather like a Lord of the Rings character, but that could be good, depending on the person ;-) Grace is very common right now, but I can't say I've ever met an Elowen.
ETA: Lyla is very pretty and elegant. My friend just had a baby girl this morning and named her Lilah Penelope. I think Lyla is just the person you described.
ETA2: Callahan sounds like a last name; Vandom sounds so random ;-)