The Haydn-Haus museum in the centre of Eisenstadt's old town, in the road now called Joseph-Haydn-Gasse, is where Joseph Haydn and his wife Anna Maria lived for 12 years from 1766, when Prince Anton Esterházy appointed him Kappelmeister at the Esterházy Palace. He sold the house when the Esterházy family and their servants – including the musicians – began spending the Spring to Autumn 'season' at their new and remote palace at Esterháza, in Hungary; he then lived during the Winter months at an apartment in Vienna.
He had a little difficulty raising the money to buy his Eisenstadt home, and he came to an agreement with the previous owner – who continued to live on the ground floor – to pay by instalments over a number of years. It seems that the Esterházys also provided some form of mortgage. The small garden of the house backs onto the Schlosspark, and the palace itself is about 200m away at the top of the road.
Only a few rooms, but surprisingly large. Paintings and drawings of course, and some furniture of the period, plus a piano from 1780, and an organ dating from 1797 which was originally in the Bergkirche. A helpful and friendly lady on reception.
There was also a small Hummel exhibition, in a part of the house next door where they stage temporary exhibitions: the much under-rated Johann Nepomunk Hummel (1778-1837) followed Haydn as Kappelmeister at Eisenstadt from 1804 to 1811. He had received free lessons (and accommodation) from Mozart in Vienna at the age of seven, such was his promise at an early age, and later did many important things in publishing and copyright, as well as being a significant classical composer and one of the outstanding virtuoso pianists of his day; I caught up with him later in Weimar.
UPDATE [June 2009]: Just back from another visit to Eisenstadt, where I found that the house (as well as the regional and church museums in the town) has had a makeover in honour of the 200th anniversary of Haydn's death. Nearly all the furniture has gone, and many new pictures and other documents in glass cases have been added, accompanied by a good audio guide. The Bergkirche organ has been moved to the Museum of the Eisenstadt Diocese, in the Catholic Church nearby in Joseph-Haydn-Gasse. It's currently much more informative than it was, but I do feel that some of the character and personality has gone. Much of the new material, especially original manuscripts, will return to its owners at the end of this anniversary year, so there will be some further rearrangement. Photography not allowed now.