Heh, hardly one hit wonders!

Peaches and Herb have been around since the late 60's but were biggest in the late 70's--disco era. "Reunited" was probably their biggest hit (very popular at school dances), also "Shake Your Groove Thing" (now there's a disco classic!).
There've actually been several "Peaches", only one Herb though.
I think they're still around, playing clubs and lounges, that sort of thing.
But if you were born the year "Reunited" came out, I'm not surprised you haven't heard of them.

This link plays clips if you want to hear:
Peaches And Herb 
I feel old now...