I think Italy blows every other nation out of the water.
Best set of inventors by far: The following inventions among many others can be credited to Italians: construction: paved roads, arched bridges, aqueducts; art and music: piano, harpsichord, violin, viola, cello, bass, opera; science and technology: electric battery (Volta), telephone (Meucci), radio (Marconi), microprocessor (Faggin), moveable type (Castaldi), loudspeaker (Marzi), sound on film (Rappazzo), thermometer (Santorio), barometer (Torricelli), compass (Gioja), seismograph (Cecchi), telescope (Galileo), nuclear reactor (Fermi), internal combustion engine (Matteucci, Barsanti), first petrol engine (Bernardi), steam turbine (Branca), jet engine (Campini), carburetor (DeCristoforis), hydraulic motor (Ramelli), helicopter (Forlanini), hydrofoil (Forlanini), seaplane (Calderara), motor scooter (D'Ascanio), eyeglasses (Spina, D'Armate), torpedo (Luppis), revolver (Broccu); food: espresso, capucinno, pasta (not invented in China), pizza.
They had the best set of explorers: Marco Polo, Cristoforo Colombo (Christopher Columbus), Amerigo Vespucci (America), Giovanni Caboto (John Cabot), Verrazzano
Best artists and sculptors: Leonardo DaVinci, Michaelangelo, Botticelli, Ghiberti, Bartolini, Donatello, Rafael, many others
Composers: Monteverdi, Cavalli, Vivaldi, Verdi, many others
Writers, historians, and philosophers: Ovid, Livy, Lucretius, Pliny, Plutarch, Seneca, Virgil, Cicero, Boccaccio, Petrarch, Machiavelli, Cicero, Marcus Aurelius, Dante, Thomas Aquinas, Anselm, many others
Pretty much all of the so-called 'finest' physical things in life are made by Italians: the finest paintings, finest sculpture, finest foods (maybe competing with French food), finest clothes, finest cars (Lamborghini, Ferrari, Pagani), finest construction and building materials. No other nation comes close to matching Italians for craftsmanship.
Anyone have any serious challengers?