It depends. Many people recommend southbound, however we did northbound and were very happy we did. The further north you go, the more spectacular the scenery is. The first day or so out of Vancouver or Seattle, frankly, the scenery is a bit boring, compared to further north. The Inside Passage is ok, but Glacier Bay, etc., is really spectacular. If you want to have the most spectacular scenery at the BEGINNING of your cruise, it seems to me that you will be disappointed, the further on you go during the cruise. That's why we booked northbound, so that the most spectacular sights were at the end. It depends also on what you are going to do AFTER your cruise. We did a few days in Denali after the cruise, so if you're going to do that, it really makes more sense to me to go northbound.