The music of Rossini's has been featured in Bugs Bunny cartoons and TV commercials, but is best heard in its original setting, where its infections charm and bubbling joy are given free reign. In the Met's new production, by theatre director Bartlett Sher and his Tony Award-winning team from The Light in the Piazza, the dashing young Peruvian tenor Juan Diego Florez sings one of his greatest roles: Count Almaviva.