I loved Florence too! On our 11 nt trip to Italy last June, I allotted 5 nights for Florence and it wasn't enough. Like
@tink1970 I would be ok not returning to Rome, but very glad I was there once. I thought Venice was fine, and although it was stinky and crowded, I loved riding through the canals and wandering the maze of crooked streets. St. Mark's Square and the Basilica area are just nuts, but once you get away from there I think Venice is charming and I'd go back. But Florence, wow, I definitely want to go back there. We arrived there on a Saturday evening, and talented musicians (and full-on orchestras) were playing in the streets, and there were lots of people but it didn't feel frenetic or rushed. Our best meals were in Florence for sure, and we bought some really nice leather pieces. We also chanced upon watching an annual parade celebrating calcio storico go right by our hotel, with people all dressed up in medieval regalia playing instruments. It just felt magical there.
Niagara Falls, Jamaica, LA (unfortunately DH's family lives out there so we go fairly frequently), Cancun, Acapulco, Puerto Vallarta, Belfast.