Just returned from a week in Rome and thought it helpful to pass on good info on restaurants there which are worth checking out. Several of these I have eaten in over 3 visits covering 8 years and my opinions have not changed on them, with one exception.
1. Best dinner value in Rome: Ristorante Marcello (Via Aurora 37; tel. 06 481.94.67) located on Aurora between Ludovisi and Lombardia, 2 blocks in from Via Veneto and the high-class hotels. Third visit, had the same meal. They offer a set meal which your waiter will know of if you ask for it. Starts with mixed antipasti (they brought us 7 bowls to help ourselves from: lentils, cannellini, grilled zucchini with parsley, a very creamy ricotta, grilled red peppers, peas with lima beans, and grilled eggplant). Primo piatti is a large platter with 3 different pastas in 3 different sauces (we got fusilli with a red sauce & olives, penne with creamy asparagus sauce, and rigatoni with a fresh tomato sauce). By this time, you can barely eat any more, but then they bring the meat course: a large chunk of roast veal (which they slice for you) on a platter with roasted potatoes and a bunch of arugula/corn kernels/tomatoes. There is so much on this platter that we always ask them to wrap up what's left; it was enough for the next day's lunch for 2 people. We drank the house wine in glass pitchers: 1/2 liter white, 1/2 liter red. This was the best price of any meal we ate in Rome: 60 Euros (service not included). The restaurant, being in a classy neighborhood, has a very nice ambiance and there are lots of locals eating there.
2. New to us this year: Da Robertino (Via Panispernia 231 between Via Cavour and Via Nazionale, but closer to Nazionale; tel. 06.47.40.620) Roberto himself is there and will provide you with a great sample of his specialties (do a Google search and find the website with a picture of him, then tell him you saw him on the internet - a very gracious man). Seafood is his thing. He served us a selection of antipasti: seafood salad (strips of calamari, shrimp, etc. in oil), grilled octopus (the most exquisite flavor I ever had, served hot, the flesh tender not chewy), smoked halibut sliced very thin, and zucchini flowers stuffed with mozzarella and anchovies. One of the house specialties is carpaccio of swordfish, but he did not have it that night so I can't judge it. Primos were a spagetti with clams and mussels (nothing extraordinary, but good)for me and a seafood risotto for my wife (we both liked it a lot). We made one mistake in allowing Roberto to order for us: he suggested an oven-baked seabass with potatoes which was quite good, but we were already quite full and this one dish added 44 Euros to the bill! Total with a bottle of Roberto's Frascati house wine was 104 Euros plus service.
3. Ditirambo (address is in Piazza della Cancelleria, but it is not in the square itself, rather on a short street that extends from the center of the square. This is just outside the Campo de' Fiori.) When we walked in just before 1 PM for lunch, they were not yet open, but a lady was making ravioli in the front. This restaurant was a good find for lunch: to start, we tried a "soufflé of anchovies and cauliflower" but there was nothing about it that resembles an egg-based soufflé. The cauliflower was a purée which surrounded the mounded anchovy dish. Unusual but good. They also offer a serving of duck and goose meats in a salami and bresciaole style. Primo offerings include the ravioli made as we entered: it is stuffed with pumpkin and a slight taste of almonds - very flavorful and pleasant to eat. Also had tonnarelli (long noodles) with black pepper and goat cheese, the pepper being very flavorful and the cheese serving to bind. Ate paccheri de Gragnano (like rigatoni) with duck sauce, very enjoyable. Can't comment on main course, as we stopped with pasta.
4. Pasqualino (Via dei Santi Quattro 66, a street which runs into the Piazza del Colosseo on back side of Colosseum). Not a bad place for a lunch. Had fettucini with fresh porcini mushrooms which was outstanding. But second time I was not happy with the meat dish ordered: this time I ordered oxtails, last time rabbit. Both times there was far too much bone vs. meat. this is somewhat to be expected with the oxtail, but the rabbit was more bone than meat.
5. Girarrosto dal Toscano (Via Germanico 56, just 3 doors from Via Ottaviano and very near Vatican Museum) Always a wood fire in the large grill and most Romans know this as a good place for grilled steak or other meats. Pastas are also good, especially Giulio Cesare and rabbit sauce varieties. Loaded with locals, not tourists. Two doors away is a nice grocery store/café/candy store with an excellent selection of foods to stock up on.
6. Cannavota (Piazza di San Giovanni in Laterano, on the square facing the side of the Basilica, not its facade) Good family restaurant with nice atmosphere and mostly local clientele. Excellent pasta is linquine alla reviglio (sometimes other pastas used alla cannavota)with nice seafood-based sauce.
7. Not a restaurant, but worth a stop: Panella "L'Arte del Pane" (Via Merulana 54-55, on a corner about 5 blocks down Merulana from Santa Maria Maggiore) A very fine bakery which offers foods you can take away: multiple pizza styles you won't find elsewhere (cut to your order), delectable rice balls with prosciutto and cheese or other ingredients, and daily specials, all of which are delicious. They will heat them up for you if you ask. Their pastries and chocolates are very rich and worth a splurge. There is also a small grocery section of the store with multiple varieties of pasta, flour, etc.
Hope you who go to Rome find these to be useful places to visit. Don't miss the big meal at Marcello!