Nicest place to do your evening shopping is at SoFo in Södermalm. A hip place with more cafes, bars and smart shops you can wish for in Stockholm.
The last Thursday every month there is the SoFo Night when most shops are open until 21:00.
Enjoy a great evening and great shopping at local small shops that have a completely different atmosphere than the large chain stores you find at every shopping center all over the world. Most gallerias are usually same, same and quite boring.
Make your shopping into something special and combine it with a nice evening out on town, there is no place better that SoFo in Stockholm.