What are your favorite restaurants in Rome and why?

IMO, the very best restaurant is, without any question, La Pergola at the Cavalieri Hilton. It offers the most refined food in the city.
On the second rank, I would placa El Toula (via della lupa). In a more traditional ambiance, they serve an outstanding menu and offer excellent service.

Pietro Valentini's near the Pantheon. It is named after the friendly owner who will probably meet you at the door. Restaurant is small, 15 tables, food and service are excellent. Price is reasonable. Highly recommend.

My most memorable meal was at La Tartaruga on a small side street not far from the Campo dei Fiori...I found it on the Fodors website. It is a small family run business with only about 12 tables. We were staying in Rome a few nights on each end of our trip and had made a reservation for the later part of our trip. We told the owner that we were on our way to Campania and would be back in a few weeks time. On the night of the reservation, we were warmly greeted by the owner who remembered that we had gone to Campania and welcomed us back to Rome. The meal from start to finish was mouth watering. The Mountain Nettle Risotto will never be surpassed. The service was attentive and kind...a bargain meal for 100 Euros by any standard.

We also very much enjoyed our lunch at L'Orso 80. We ordered the house Antipasti and watched them fill a double table with almost more plates than I could count. It wasn't so much that the food was amazing...it was very good but the experience of dining with the locals...eating and drinking wine for most of the afternoon...it was a lunch I will always remember.

Has anyone been to Felice in Testaccio??

L'Orso 80. Love this place, food was good and service was great. My kids loved it to. Good antipastos, just be careful antipasto for one feeds 2, large portions.

L'ORSO 80, VIA DELL ORSO 33

We each have our own opinions of course, but let me say that we went to La Tartaruga after seeing a number of recommendations for it here. It was probably our most disappointing meal in Rome. Not bad, just nothing special. I will say the hosts were very welcoming which was nice, but the food was merely so-so and quite bland, particularly the asparagus soup and my tagliarini with porcini (although I couldn't even find any porcini in it). The main veal courses were OK, but again quite bland., and came with mashed potatoes smothered in gravy. What's more we were surprised that on a Saturday night at 9:30 it was half empty, and all the other people there were tourists like us -- always kind of a downer. It was one of our more expensive meals in Rome.

We loved Il Bacaro where we sat outside in a tiny street and dined on some most unusual dishes superbly flavored.

Our new favorite became Osteria del Pegno, a small, candlelit and fresh flower filled, and rather romantic but rustic place just off Coronari on Vicola di Montevecchio. Great food, warm and welcoming service.

I've been to Felice and wrote a detailed review on Slowtalk. The food was great and very inexpensive. The owner is everything legend has made him out to be. If you can get a reservation you are in for a memorable meal.

I second the Pergola - fabulous meal, wonderful chef and great setting.

Here's another one we went to for the first time this year.

Ristorante da Alceste – Al Buon Gusto
Corso Rinascimento, 66/70
Tel: 06 68 61 312

Wonderful restaurant, serving the freshest seafood I’ve ever had in Rome.
Very modern, with a rather stark design, the food is the star here.
There is no menu per se – the waiter simply tells you what is available.
I chose an entree of raw seafood and my husband chose the cooked seafood. Small platters, bowls and dishes arrived and were arranged on the crisp white tablecloth…. One platter offered an arrangement of shaved raw sea bass, three large translucent shrimp, a large scallop in its shell and drizzled with lime juice, lemon zest and olive oil.
Among the cooked offerings was a paper cone of tempura battered deep fried baby squid and small red mullet filets in a fresh tomato sauce.
For the main course we had a beautifully baked whole sea bass with fresh tomatoes and chunks of potato. Delicious.
Dinner for two with a bottle of white wine, dessert and coffee was E 180,-

That is a shame that someone had a negative experience at La Tartarga...they rate very high from the reviews on this website and I was not disappointed at all. I wouldn't even share my meal with my husband...not even a taste because everything on my plate was wonderful.

I also enjoyed Osteria la Pegnol, and especially Il Bacaro. They serve the most wonderful sliced beef in mandarin & mustard sauce.

Also, Da Francesco, Piazza Fico, smoked salmon that is divine and the best pizza I've ever had. Mmmm...

Has anyone been to Agata e Romeo, El Toula, La Rosetta, Quinci & Gabrieli, Montevecchio, Dal Bolognese or Antico Arco?

My favorite restaurant in Rome was the Nuova Stella right near the Termini station. It was recommended by our hotel and it was a great recommendation. The service was great, the prices were reasonable and I had the BEST eggplant parmagiana I have EVER had in my life (and I've had it a lot of places). My husband's linguini with seafood was also to die for. I would highly recommend it to ANYONE in that area for a wonderful and fun dinner.

I've been to Agata e Romeo and da Bolognese. Agata is great, wonderful food, service and elegant ambience. Da Bolognese is OK but nothing I'd go out of my way for.