Favorite thing: Approach Helsinborg by ferry from Denmark to get the best feel for the city straight away. From the deck of a ferry, you can make out the City Hall and then Kärnan fortress high on its hill and you can imagine the defense needs.
A very popular thing to do in Helsingborg is taking the ferry to Helsingör, Denmark.
There are two different ferry-lines that will take you there, Scandlines and HH Ferrys, and both will do a good job.
For some reason I always go with the first one, not sure why though.
The trip takes just 40 minutes, and it's possible to get onboard by foot, or bringing your car with you. Helsingör is a very nice small city, but it takes just around 40 minutes by car to go down to the danish capital Copenhagen.
A good thing with Denmark is that the beer is much cheaper than in Sweden. Many people therefore takes the ferry to buy cheap beers or other alcohol, and then turn back immediately to Sweden.
The ferries goes from the trainstation-building, Knutpunkten, where you also will find the bus station, and a lot of parking-places for your car.
Fondest memory: For more ferry-information:
There you'll also find prices for the different trips. There is a boat leaving Helsinborg/Helsingör every 20 minutes during the day.
Favorite thing: While you are in a ferry going from Denmark to Sweden and backwards, you won't feel that you're in the sea, as the distance is really tiny and all the time you can see both shores very well.