Had a slice at Pizza Grupo last night on Avenue B at 12th. It was excellent and reminded me of the thin crust pizza that I've had in Rome and Florence. Tasty sauce as well. They make a personal pie for 4.50 and a large (16") is 9 bucks. Can't wait to go back and try a whole pie with some toppings.
Also would suggest having a drink at Rue B's next door, They make a pretty tasty Blood Orange Cosmopolitan and usually have live jazz most nights of the week.