The Red Roof Inn BWI Airport is a good place to stay for a night or two while in Baltimore. There is a free shuttle from/to the airport which makes it convenient if you don't want to drive. I arrived late at the airport around 2300, but the area where the shuttles enter was still extremely crowded. As such it took about 30 minutes for the shuttle to arrive. Once at the hotel I was checked in quickly and found my room on the third floor. There is an elevator in the middle of the hotel or a set of stairs adjacent to the reception.
The room had two beds and a small work table along the wall. The lighting was somewhat dim, but wasn't an issue. The television was mounted on the wall in between the beds. The pillows on the bed could be softer as they were not comfortable at all. The bathroom is small which made it hard to move around, however wasn't much of a concern. The shower had plenty of hot water and pressure. A unique thing about the room was that the air conditioner and heating were two separate systems. The air conditioner worked well and wasn't that noisy.
You could hear the traffic outside and some noise from the adjacent rooms, but it was minimal and wasn't a distraction. The only noise problem you will have will be from guests outside at 0300 in the morning yelling and laughing at each other who could care less that they are at a hotel.
The best part of this hotel was the staff and shuttle. Not only will the shuttle take you to the airport, but it will also take you to the nearby light rail station and nearby restaurants. The shuttle is at no extra cost.
I would definitely recommend the hotel. It is simple, but is clean and conveniently located as long as you are not looking at staying downtown. Public transport (minus a taxi) will take awhile depending on timing.