If one is in southern Tuscany, I Due Cippi da Michele in Saturnia. The owner tales great pride in his bistecca florentina. Certified organic Chianina beef that he proudly displays at the entrance, cuts and cooks himself.

Not cheap at EUR 75 / Kg (Oct 2012) but lots of locals go there to eat it (and order kilos of the stuff).

http://www.iduecippi.com/