I stayed at the Hotel Carlos V between Oct. 14 and 16, 2005. I paid 39 euros night, not including the VAT tax. No continental breakfast was included. The best reason for staying at this hotel is the location, cleanliness of the room, and free internet. The hotel is within walking distance of restaurants and the main attractions (except for the Alhambra, of course, which you need to take a bus or walk to). Some of the staff speak English. The hotel is located on the 4th floor so you need to buzz them at the door and go up the elevator to reach the front desk.
Pros:
The room and bathroom is nice, clean, and modern. The bathroom shower has those massage nozzles. The room comes with a very comfortable bed, desk, closet, and TV. There are plenty of outlets to charge your electronic equipment. You just need to make sure that your converter or plug has a round end or else it won't fit into the wall. The front desk may have a converter if you don't. The hotel provides towels, soap, shampoo, etc.
Okay, cons. I'm not a smoker and the odor from cigarette and cigar smoking is prevalent in the hallway and front desk area. I think the front desk staff smokes. The smell doesn't get into your room but it hits you when you open your door. Next, it's noisy. Not from any elements outside but from the lobby and guests. Like everywhere in Europe, the walls and doors are thin so you can hear the TV, phones ringing, guests walking, talking, and moving their luggage in the hallway. One of the front desk people brought her kid in the evening and the kid cried for hours, making it hard for anyone to sleep.
All in all, loved the room but hated the noise. If you do decide to stay here, ask for a room farthest away from the lobby. That might mute the noise and if that does, then you should have a lovely stay.