My wife and I recently stayed at the Ibis in Koblenz. Nice hotel, great location. We were within walking distance of everywhere we wanted to go. The train station is not far, and despite the close proximity, the hotel is not noisy. Also, all the people I talked with at the hotel were very good at speaking English. A real plus, since my German is not so good!
The room was clean and comfortable, and breakfast was good, too. The bar serves local beers, as well, and the bartender was very friendly.