Vienna is a beautiful city. For some reason (might be connected to the wine-tasting festival Martiniloben held in November every year just outside Vienna) I've mostly visited in late autumn, but to be honest, does anyone mind glüwein being sold on every street corner? This last visit we (Maria & Mattias) focused on Stephansdome, schloss Belvedere and the art exibitions at Albertina.
Schloss Schönbrunn, on the outskirts of Vienna (just take the U4 to Schönbrunn and the castle is right round the corner), is beautiful even when November winds are freezing and dark clouds cover the sky. The (audio-)guided tour through the castle gives an intimate insight in the lives of the Habsburg-family, who spent much of their time there, and I must admit I was almost moved to tears when parts of Maria Theresa's diary was read. 
The gardens are also wonderful, not too large (as the one in Versailles), but with a surprisingly private feel to it. Exploring the "woods", discovering the "Roman ruins", and making friends with local wildlife makes it a great experience. We will have to go back in summer. 
