If you're planning to spend an extended period of time in Florence I highly suggested picking up an Amici Degli Uffizi card. Our family version of the card cost 100 euro, lasts all year, and gives us "free" entrance into 15 museums in the city. The best part? The card also allows us to skip the line at the Uffizi -- which saves hours during some times of the year.
We use our cards all of the time. On Thursday we popped into Boboli Gardens for about an hour. We brought a blanket and just relaxed in one of our favorite, quiet parts of the garden. On our way out we checked out the set up for the outdoor Opera Festival. We've heard all of the performances from our apartment and it was neat to finally see how they have the stage set up.