Im mixed. I love the city, but there are a lot of other places I'd rather see because i have spent so much time there. You mentioned the top 5 -10, a walking tour of the history of the city would be pretty cool, Medici tours, some more of the museums that were not mentioned....
But the crowds that I saw last month, eff that. I agree with you.
Driving the country side in Tuscany was great, if you can do 3-4 hour stints in a car.
I loved the Ducati Factory / Museum tour outside of Bologna, and the drive to get there, but I know that isn't for everyone.
That said, we did a couple tours this time in Rome, and the lines were just as bad (esp the Vatican).