As much as she likes being home in Germany for vacations, we're both pretty much settled on staying in Copenhagen. She certainly wouldn't want to live in Berlin, but of course she may be biased, coming from rural southern Germany herself.
For reference, she comes from a small town just south of Stuttgart, and she's lived in Munich, Aachen and Mannheim in Germany, and Dublin in Ireland, before moving to Copenhagen. So I figure she's got a reasonable comparison to make :-)
Copenhagen is simply outrageously amazing for biking, public transport, cultural events and food selection. I honestly couldn't imagine living anywhere else, and I've lived at both ends of the rural/urban spectrum in Denmark, as well as visited a fair few places around the globe. I wouldn't want to live in the city centre (way too expensive and cramped), I'd like to have a garden and such. But no more than 30-45 minutes by public transport to the city centre.