We read this forum and learned about K&K Opera Hotel in Budapest. We are just leaving the hotel after a several night stay and it was fantastic. It's located right next to the opera and is easily accessible to most of the key attractions. The hotel was able to get us front row seats to the Nutcracker just a day before the show. We have no idea if we just lucked out but they are very responsive and a great resource. Also very reasonable - a terrific find.