Harry's Bar 
In summer, tables are placed outside. If you want to dine outdoors but avoid the scorching sun, there's an air-conditioned sidewalk cafe open from May to November. Meals inside cost about double what you'd pay outside. In back is a small dining room serving some of the finest (and priciest) food in central Rome. 
Address: Via Vittorio Veneto 150, 00187 Rome
Tel: (+39) 06 484 643
Website: www.harrysbar.it

La Bottega del Vino
This old-fashioned setting comes complete with terra-cotta floors and long, battered wooden tables. Everything acts as a foil for the Italian and French wines served here. Priced at 5 to 18 ($6-$22) per glass, depending on the vintage, most come from well-known or obscure vineyards throughout Italy. Affordable snacks and cold platters are available as accompaniment.
Address: Via Santa Maria del Pianto 9/a, Rome
Tel: (+39) 06 686 5970

Cafe Rosati
Caf Rosati, which has been around since 1923, attracts guys and dolls of all persuasions, both foreign and domestic, who drive up in Maseratis and Porsches. It's really a combination of sidewalk cafe, ice-cream parlor, candy store, confectionery, and ristorante that has been swept up in the fickle world of fashion. 
Address: 5A Piazza del Popolo, 00187 Rome
Tel: (+39) 06 322 5859