My favorite cruise was the old "Green Goddess" Caronia world cruise. It was the trip of a lifetime. However, I was just a kid. My favorite, more contemporary cruise was Nantucket Clipper to the Maritime Provinces and New England. Because NC is such a tiny little ship, we traveled down waterways that no big ship could ever have navigated. One area, St. Peter's canal even scraped NC's sides. Because ships of any kind are so rare in that part of the world, the locals would come out to see us in most places. No casino, no show lounge (only two public rooms), no formal nights, historian, naturalist and whale expert onboard. The cruise was so beautiful, the food exquisite (I watched them bring very fresh supplies onboard at almost every port) and so many wonderful teachers onboard, passengers as well as crew. I would love to go back.
Favorite ship these days? Royal Princess without question.