Room Recommendation in Florence - One night

Check out Hotel Casci. About a 12 minutes walk from train station, and 5 minutes up via Cavour from the Duomo. Clean rooms, nice people, elevator, no views but great double-pane windows mean quiet at night. Have stayed there 6 times and happy every time EXCEPT don't let them put you in the "Bellini room" in the stairwell; you get noise there as people arrive. Other than that, it's a great hotel for very fair price. And wonderful wonderful breakfasts. Check their website for photos and reservations....

You might have a look at Katti House as it's relatively close to Firenze SM Novella (the main rail station in Florence). It's in a nice area and close to some of the main sights. if you decide to stay there, it would be a good idea to book early!

I've stayed here. Great location.

http://www.touristhouseghiberti.com/

Near the train station, Hotel Paris. Near the Duomo, Hotel Bigallo.

By the Pitti Palace and Boboli Gardens.

http://mobile.hotellascaletta.it

Great staff and a rooftop terrace.

I booked this place. It's a B&B and better priced. I hope it was a good choice.
I'm still waiting on my RS guidebook to be delivered. Maybe I should have waited to read his recommendations.
Locanda de' Ciompi.

I stayed in the Hotel California which was very close to the Duomo. I would strongly recommend it.

Hotel Pierre- http://www.hotel-pierre-florence.com/

Short walk to all major sites. Fantastic staff and great continental breakfast. The city is mostly flat and extremely walk-able.

My wife and I just returned form Italy and were surprised how close everything was in amazing Firenze!

Enjoy!

We stayed in a B & B called Le Stanze Duomo very close to the Duomo Complex. It is a good place with affordable prices and a decent breakfast at a cafe nearby. Everything worth seeing is in a walkable distance. The only bus ride you really need to take is up to Piazzale Michelangelo/ San Miniato Church and back for a view of the historic centre at sunset or after dark..It looks great and worth the journey..

Dear OP,
Don't worry about your hotel. If it fits your budget and has decent reviews - just go with it. My personal recommendation is hotel Pendini - stayed there twice. If your hotel is anywhere near Santa Maria Novella Complex or City Center - you chose well. If your hotel does not offer breakfast - that's an easy fix! Just buy a pastry and coffee with the locals at a shop. Ask your desk clerk for that type of info.. All you need is a clean room, bed, bathroom in a decent, walkable location.

Dear OP,
I just looked up Locanda de Ciompi on trip advisor. It appears to be on a lovely Piazza that I didn't know existed. It looks like a fine place near Santa Croce and Bargello museum. I am not concerned about the hotel so much as the location. The train station is on the opposite side of the city enter. So, if you are hauling a carry-on or doing a backpack - you can walk to this place. Otherwise, you may want to take a short cab ride which is easy and probably not more than 10€. In fact, I would recommend the short cab ride at least when you arrive. Why? This is your first time to Florence and the streets can be a bit disorienting to a newcomer. So, hop a cab. Once you walk around a bit and you have your bearings - navigating comes more easily. However, due to your limited time - I think you would be better served by a hotel near SMN area. Cheers!

Thank you everyone for your great tips.

Yes, we would probably take a cab ride from train station as I'm sure we will be quite tired by this time. It is difficult to know where is the best location when you've never been there. We were that way in Rome. The first time we stayed in a nice hotel but much farther a walk to the historic centre. The second time we knew better and stayed right on the Piazza Navona. This was a wonderful location.

We shall see. As long as the room is clean and comfortable and hopefully quiet in a good area. A bonus if it's close to sites and cafes.

I can recommend B&B La Dimora degli Angeli which has some rooms over looking the Duomo. Each room is individually decorated to a high standard. We have stayed there twice - in 2013 and 2015 and loved it both times.

A link to a photo I posted to Panaramio taken at night from the window of our room - an unforgettable experience:

http://www.panoramio.com/photo/100537548

Regarding the cab ride -- if it seems the driver is taking you a roundabout route, just know that many of the central city streets are one-way so that may indeed be the most direct route.