I booked a triple room with 45B for New Year weekend and had the most lovely stay.
The property is an old traditional house full of character and renovated to excellent standards. It is located outside La Cite fortress, by the Cathedral. The location is very convenient, a 15min stroll to La Cite and 10min walk to the train station. This is particularly helpful if using Carcassonne as a base to explore the region -- the city is very well connected by train to Toulouse and Narbonne, etc.
My party stayed in the red room which has high ceilings, comfy beds and a small bathroom with great water-pressure in the shower. The room does not have a TV or fridge but it is large, airy and spotless clean.
Breakfast is taken in a lounge (or in the garden with pool during the summer). It does not include "hot foods" but the pastries and baguettes are very fresh, and compotes, juice and hot drinks of excellent quality.
However, even though accommodations are excellent and location is good, what makes this B&B special is its owners! They are the most lovely hosts of any B&B I have ever stayed in, offering to make restaurant reservations at booking, giving us maps and information about the town, providing free wireless internet, serving breakfast at whichever time we chose and even giving us a lift to the airport...without ever overstepping or bothering us. Truly the most hospitable and well organised B&B owners!
I most avidly recommend staying at 45 BB! Excellent stay!