One place I always try and get to when I am back in Tuscany, Italy, is the Piaggio Museum at Pontdedera. Much as I enjoy wandering through the beautifully presented and very varied types of Vespa, and Piaggio trains planes and automobiles, it's the collection of historic Gileras that I like to head to. Squashed in slightly unceremoniously on an upper walkway above the rest of the museum, this collection is what was left in the Arcore factory when it was sadly shut by Piaggio in 1993 after 84 years of continuous motorcycle production. Gilera had a truly glorious history and racing success to match that of Norton or Moto Guzzi, so it's a shame to see its name used pretty much on just scooters nowadays, though of course the late and wonderful Simoncelli won the 2008 250 World Championship on a Gilera.
Highlight in the collection is the first motorcycle built by Giuseppe Gilera in 1909, the single cylinder 500cc VT 317, but there are many more, including the historic four cylinder Rondine, which set the pattern for the eventual all victorious Japanese race bikes.
Anyway, if you find yourself in the area (equidistant between Pisa and Florence), it should be a definite choice on the itinerary. More information here:
http://www.museopiaggio.it