Itineraries and onboard activities may be the first things you consider when planning a cruise, but don’t underestimate the value of a stylish stateroom. It’s tough for even the most seductive port of call or thrilling day zip-lining across the Lido Deck to make up for sleeping in a drab, windowless box. The World’s Best cruise lines—chosen each year by our readers—know that in compact cabins, every detail counts. Especially for cruisers on extended itineraries (sometimes as much as a month in length), cruise quarters are more than a place to store luggage; they are, temporarily, home. Comfortable rooms can even turn skeptics into devotees of ocean and river travel.