This thread i s a bit old but i would like to give my feedback as well.

Rome
Both the Hotel de Russie and The Portrait Suites (last one i think belong to Ferragamo Family and has many decoration with the official logo of the brand...it is just up their boutique in Rome) works fantastic for me in Rome.
I prefer Hotel de Russie because being a bigger hotel deliver come complete service.

I hear very good reviewv about The Eden, but never been there.

I even like The St. Regis in Rome, spectacular hotel old style. But recently the dining option were very limited and for dinner we could only have dinner at the lobby bar (they said restaurant was under renovation).

Florence
I have been and like particularly the Hotel Savoy (very centrally located) and The Westin Excelsior. Savoy more modern, Westin old school.
Four Season is gougeous but not been there yet

Naples
I'm afraid that many people reccomend not to visit Naples. It's a wonderful City, my native city. But, yes, There are several minus that I understand can bother many travellers.
BTW. Best in town are supposed to be The Grand Hotel Vesuvio and The Excelsior (both on Via Partenope) and The Parker (not very familiar with the last one i must say).
About the coast I can name at least 10/20 fantastic hotel. Not to be missed for sure
Il San Pietro....do me a favour and do not compare this with anything else... Il San Pietro is unique... end of the discussion
I love as well Mezzatorre Resort in Ischia. Fantastic location as well.
And I'm a fun as well of Ravello with Villa Cimbrone and Palazzo Sasso on the top of list whyle i do not favour really il Caruso, that is a very beatiful hotel anyway i must say.
Santa Caterina is a nice hotel as well very close to Amalfi...and i like once in a while The Excelsior Vittoria in Sorrento.

best
The_Daddy