Warsaw...where I visited for the first time by the end of June, 1996. Later on I was there as a research assistant in University for 6 months. Lastly, I was there for a conference in July 2004.
The first time was in summer for only two days. Second time was longer. I lived the amazing Autumn of Warsaw where you can witness all colors of nature. However the winter was really harsh. On the other side the fantastic scenes of the city under snow and of course the friendly nature of the Warsawians makes you forget the freezing winter.
I advice you all to visit there in any season. I advice you not to go to touristic places. I really hated them. Try to have Polish friends and spend time with them, try "nazdravi!"(cheers in polish - before you swallow a glass of vodka).
Especially for the ones who are interested in Urban History, History of Worl War II, or history of Holocaust. I insist on advicing to go to that land of beauty, romance and sorrow .... and ... of course wonderful Vodka. I advice you to go there by 1st of November in All Saints Day.
More info will come later....