From my recent trip:
Cuccagna - 14 via della Cucagna
family owned place near Pza. Navona -
more local than tourist - family owned - nice for lunch, and would be a great place for a romantic dinner
I can reiterate the many rec's for Giolotti (via Uffici del Vicario 40)
For pizza I preferred Ristorante da Francesco over Baffetto -