For dinner, Antico Arco is an elegant and intimate restaurant perched up on the Gianicolo Hill which you can walk up from Trastevere if your'e feeling energetic and love views over Rome. It's all about the food here though, not the views, which is some of the best in Rome. Well cooked roman dishes and a good wine list. Although this is towards the top end, it's still half the price of London restaurants of this quality. Their Antipasti, 'Flan Cippola' (onion flan) is famous. Eat two! If you go in a group, they also have this great habit of bringing 'piccolo' (mini) dishes of everyone else's selections so everyone can try each dish. How cool is that!
Pizzale Aurelio 7, Gianicolo, Roma (by the Arch of San Pancranzo)