Sao Paulo's fascinating for dining. Every day of the week has a food that people eat only on those days. On Sundays, the whole city turns out for "Pizza Day." My favorite two spots are Pizza Margharita (Jardins - corner of Haddock Lobo & Tiete) and Pizza Braz (location in Moema has a good selection of wines and great vibe - go early to avoid the rush). Saturdays and Wednesdays are for feijoada (try Bolinha in Jardins). You get the idea.
Other highly recommended places, which all should have decent-to-great wines are:
* Brasil a Gosto (Jardins) - year old place with local, high-quality Brazilian cuisine and phenomenal cocktails (try the starfruit caipirinha)
* In vino Amici (Itaim) - intimate bar/restaurant with a large wine cellar and sommelier who knows his wine; close to all the new offices
* Colher de Pau (Itaim) - great lunch location if you want to try regional Brazilian fare
* Mercado Municipal (Downtown) - worth the trip to the huge market downtown to sample all the cheeses, olive oils, and pasteis de queijo minas (cheese inside fried bread - the name doesn't do it justice)
* Bread & Company (Ibirapuira - posto 7) - best brunch place in the city, even the papaya is delicious