Franco is memorable for many reasons, but perhaps his legacy is that he took over the helm of Brazil at a tough time in 1992 and within two years had got the runaway four digit Brazilian inflation rate the time under control. He did it by bringing institutional stability to a then-fraught country and his key move of appointing Cardoso as his FinMin who did the heavy financial lifting, brought the economy back into the bound of reality and subsequently won himself enough political capital to succeed Franco in 1995.
One datapoint about Franco, however, is that he left office with a 90% approval rate and not even Lula could beat that. Today President Dilma Rousseff has declared seven days of official mourning in Brazil, which also gives you an idea of the importance of the man in his society.
Itamar Augusto Cautiero Franco, 1930-2011. D.E.P.
UPDATE: Felix Salmon points your humble scribe to the Bloomie report of Itamar's passing