Both Kate Minchilli and Katie Parla give food tours. There are many, many available, but these two are particularly good. You can't go wrong with either one of them.

PIERLUIGIi - One of the top restaurants in Rome. Very romantic, upscale, somewhat formal. Great, accessible location. Go if you want seafood. You can also eat outdoors here. Very expensive, but worth it.
JARDIN DI RUSIE - It's supposed to be great. I haven't eaten here. I believe it is outdoors in a courtyard. Great reputation. But it's in the Hotel Russie. Prices are usually jacked up, and I don't feel like I'm in Rome when eating inside of a hotel surrounded by foreigners, so I haven't gone. Easy location.
MOLTO - Is really Molto Cantina. Cantina means wine cellar. They also have a take out menu, which doesn't bode well. Location wise, it is inaccessible. You cannot walk to it, you will be on the outskirts of Rome. I wouldn't.
ASSUNTA MADRE - Good location. Don't know the place. Specializes in seafood. Looks pretty darn good to me. The only thing that puts me off is that they have a sister restaurant. It is located in London. How can a place guarantee the same meals in two different countries, claiming to bring fresh fish from local Roman waters? Makes it sound like it's trending towards a chain or a corporate restaurant.

· GIRARROSTO TOSCANO - Having just come from Florence, which is in Tuscany, why would you now eat Tuscan food in Rome, instead of eating Roman food? It would be like ordering pasta carbonara, a roman dish, in Florence.
· TULLIO - I had a great meal at Tullio, and I know several other people who had. I wouldn't say it's casual, but it is certainly not formal. I mean, don't think you are just going to a neighborhood osteria. This place is fairly upscale, but not like a Pierluigi. This is a great place to eat near your hotel.
· IL FELLINI - Looks like a nice, candlelit place. Reasonable location. The only thing that makes me think is that it says on their own homepage, "Chef Liam V che con il suo nuovo concept della ristorazione romana ha ideato il rinnovamento culinario all'insegna dell'avanguardia." This means, "Chef Liam V who with his new concept of restoring roman food and renewing it in the avant garde manner." If this is your first time in Rome, you probably want to stick with regular traditional roman food, and not experiment with an avant gard chef.
· TEMPIO DI BACCO - Looks like a good place. Good location. The only thing I think about is that there are several restaurants with the same name in Italy, one in Milan, one in Bari, one in Nocciatore. I don't know if this means that it is sort of like a chain, or if it's coincidence because the name means Temple of Bacchus, which could just be a popular choice of names for a restaurant.

In Trastevere,
· TARERNA TRILUSSA
· ANTICA PECA
· ENOTECA FERRARA
· LE MANI IN PASTA

I wouldn't eat in any of these places, even more so on the advice of a concierge. In fact, be careful eating in Trastevere. It used to be part of hidden Rome in the 80's and 90's. It's still a beautiful, must see area, but it has become completely overrun by tourists, and the restaurants cater to tourists, with overpriced, inauthentic food. It's hard to get real, authentic food there. There are a few great restaurants, but you'll have to do some homework and get better recommendations than from a concierge, who will just send you to a tourist place. Are you sure you got the name of Antica Peca correct?

ARMANDO AL PANTHEON or CLEMENTE ALLA MADDALENA by the Pantheon

I've eaten at Armando's many times. It's a roman standard as a restaurant. Always great. I don't know Clemente. It's easy to get tripped up with touristy restaurants near the Pantheon. It may be great, but their website says that they have a service where they will come to your house and prepare a meal for you if you are having a party. Sort of like catering. That's not common for great restaurants in Rome. Heck, Armando's is so successful that it's hard to find them open sometimes, much less have them willing to go to your house and cook for you.

I won't comment on the Michelin star places, that speaks for itself.