In the UK or abroad.
I love Sarajevo (not trying for indie points, honest) - pretty, multicultural and in the process of rejuvenating from the Bosnian war. Vienna, Paris, London (endlessly exciting to a country bumpkin like me) and Plovdiv probably make up my top 5.
Feel free to rate yours on culture, history, beauty, food, nightlife etc. Or just make fun of me for including Paris and London.