I can't come up with boy/girl, but for girls:Amanda and Miranda. I love both, the only thing I have against Amanda is its former popularity and thus current commonness. Boys: Brent and Kent. I really like Brent, Kent not as much, but it's not terrible IMO.
I've thought of an embarrassingly easy one for boy/girl - pity I didn't have my inspiration when I posted! Anyway, for what it's worth, how about Joy and Roy? Or, indeed, Ann and Dan?