A couple of observations on selecting tomatoes: Italians divide them into two classes: insalatari and da salsa. Insalatari, as one might expect, are salad tomatoes, to be eaten raw. People generally select them not-too-ripe, in other words quite firm, with streaks of green running through them, and with a lively acidity that complements the flavor of the greens in the salad. Pomodori da salsa, on the other hand, are for cooking and should be ripe -- an explosive red, rich, and slightly sweet too.
These are Pomodori Merinda, a Sicilian heirloom tomato that's best when still shot with green. They're also best when they're not too large, and people generally eat them raw, finely sliced because they're thick-skinned, in salads or simply seasoned with olive oil, salt, and vinegar.
More Italian Tomatoes:
Tomato Background, Info & Recipes
Insalata Caprese, Mozzarella and Tomato Salad
Anthony's Mediterranean Tomato Salad
Tomatoes Elsewhere on About:
Lush Tomato Salad
Green Bean and Tomato Salad
Mango Tomato Salad
Low Fat Corn, Black Bean and Tomato Salad