Carnival offers the usual assortment of onboard activities, from traditional napkin-folding classes, Vegas-style revues and kitchen tours to belly-flop pool contests and waterslide races. All of its ships offer size-appropriate spa and fitness facilities and have multiple pool areas. On Destiny-class ships and all subsequent new-builds save for Carnival Dream, one pool always lies under a retractable roof so it can be used year-round. Casinos on Carnival ships are elaborate, Vegas-style rooms with all the neon and flash one would expect. Carnival is increasingly experimenting with dining venues on its ships.

Royal Caribbean operates one of cruising's most intriguing fleets. Ships range from mid-sized, middle-aged ships which -- like Majesty of the Seas, for instance -- have received major updates and state-of-the-art and on-the-cusp mega-ships. The line is constantly innovating, and the three latest additions to the fleet -- Quantum of the Seas, Anthem of the Seas and a third as-yet-unnamed ship -- will form a brand new class: Quantum Class, which arguably sets the bar even higher. Quantum of the Seas (the first to be launched, in 2014) is bringing out Royal's wow factor with firsts at sea including a skydiving simulator, the first bumper cars at sea and North Star, a jewel-shaped glass capsule rising 300 feet above sea level and providing 360-degree views over the sides of the ship. It will also have inside cabins featuring real-time views of the ocean and destinations and the first single cabins with balconies.

Norwegian Cruise Line offers a hybrid cruising experience, mixing traditional elements with innovative features, amenities, and ambiance. The decor is colorful, fun and occasionally loud, especially on newer ships. The dress code is flexible and very casual. It's not unusual to see T-shirt-clad passengers dining among their more dressed up shipmates. (Tuxedos are rare.)

What began as "the little cruise line that could" has evolved into a cruise industry giant. Beginning with a 6,000-ton converted ferry chartered from the Canadian Pacific Railway, Princess operated the small luxury liner between Los Angeles and the Mexican Riviera in 1965. The line now has 16 ships sailing the globe offering approximately 100 itineraries that range from one to 100+ days and visit more than 300 ports.

Holland America ships still hold onto numerous traditions -- such as afternoon tea, the (occasional) gentlemen hosts for dancing and a quaint "chime ringing" to announce dinner. Holland America has long been one of the more traditional cruise lines when it comes to the main restaurant dining it now offers passengers more flexibility with "As You Wish" dining. Holland America recently added the Master Chef's International Dinner and offers cuisine from six continents crafted by the line's Master Chef. Evening entertainment, consistent with the Holland America experience, is fairly understated with pre-dinner cocktails generally being the liveliest time. However, there are numerous entertainment options, from disco-style dancing in the Crow's Nest and flicks in the cinema to Vegas-style revues in the main theater.

Disney Cruise Line® has selected the most stunning destinations - in the most exciting regions around the world - for cruises you and your family will not soon forget. Enjoy the service and expertise of our dedicated crew as we guide you in your exploration of international ports of call, from the Caribbean to Alaska to the Mexican Riviera and beyond. Discover, in detail, the world of delights waiting for you.

Celebrity Cruises offers an exceptional level of personal service, accommodations that are among the most spacious at sea and a wide variety of activities and amenities. Onboard, you can attend an informative onboard lecture or discover unique gifts in the upscale boutiques. Other features and services include enhanced adult enrichment programs, more interesting shops in the Emporium complex, "welcome aboard" sparkling wine and mimosas, a spa cafe dinner option that's tops in the industry, wine tastings (and the first Riedel comparative wine workshops at sea), a revamped sports deck, extensive golf programs and the innovative Acupuncture at Sea program (taking over the space once occupied by Notes on the Millennium-class ships). Innovative bar options abound, with the frozen Martini Bar and offbeat Molecular Bar.

Seabourn Cruise Line was founded in 1987 to compete in the ultra-luxury cruise market. Seabourn's first voyage was in November of 1988 on the newly built Seabourn Pride. In 1998, a consortium, which included Carnival Corp., purchased Seabourn and merged its operations with Cunard Line and Seabourn became one of their "world's leading cruise lines." Cunard, Princess Cruises, and Seabourn operate independently from other Carnival Corp. brands.

Crystal's biggest challenge is in, ironically, the main feature that differentiates it from smaller-ship luxury lines. With bigger ships carrying more passengers, it successfully offers exemplary service, outstanding cuisine and freedom of choice on such a large scale? And, it has one of the industry's highest passenger-to-staff and passenger-to-space ratios, and, perhaps not coincidentally, one of the most loyal repeat passenger bases afloat. There's a huge positive to Crystal's biggest-ships-in-luxury-class status as well; there are simply far more options, in terms of entertainment, socializing, casinos, spa and fitness facilities, activities and enrichment opportunities, than there are on its smaller luxury brethren.

Whether new ship or old, MSC Cruises emphasizes a strongly Italian-influenced ambience. For the most part, its ships traverse the Mediterranean (winter and summer) and are geared to European travelers. But, the line has made a major commitment to not only sail elsewhere (South America, Canada/New England, the Caribbean, South Africa, the Gulf), but also to expand its passenger base to include English-speaking travelers. Because of the international passenger base, announcements generally are read in Italian, French, Spanish, German and English. Life onboard, particularly when it comes to mealtime, follows a more traditional cruise schedule -- set dining times and seatmates, and a handful of optional eateries that include sushi, a buffet and an Italian restaurant.