In my job I get these questions all the time "what's the best cruise line" and "what's your favorite cruise?"
I guess part of the attraction of cruising is that both of these questions actually make no sense.
"What's the best cruise line?" How much money do you want to spend?
"What's your favorite cruise?" The one that costs the most.
No, I'm kidding, I never say that (not the second one anyway), but I guess a lot novices think of cruises as something like greyhound busses. Like the same vessel does the same itinerary all year round for set price that never changes.
The correct questions are "which cruise lines give you the best value?" and "what is your favorite combination of cruise line and cruising region?"
And even given those questions, I can never answer the question because it isn't like food - where you get the same thrill every time you eat it. Cruising is like going to the movies - where the first time you go to a certain place it is your favorite time going there, because it is all new.
As far as cruise lines, I like some more than others, but I am generally much more concerned about where we are going than which cruise line we are on. I mean if you give me a choice of cruising in the Caribbean on Silversea or going to a new & exotic location (for me, that would be New Zealand right now) on Carnival I would take the Carnival cruise in a heartbeat.
I realize a lot of people are not like that - they think vessel first and location secondary, but where a ship is sailing is very important to me, unless I am going to a place i have seen dozens of times (Eastern Caribbean), and then the ship is all that matters to me.
My ultimate ship has...
fast response for room service
Lots of hot-food choices for room service
A LARGE screen flat-panel TV with lots of channel choices, not just CNN International
A DVD player and a well-stocked DVD library
A room steward who always cleans up while I am out of the cabin - virtually invisible.
Outside the cabin:
24-hour buffet (only Princess as far as I know)
Serves a good steak and lobster
A good, hot breakfast buffet, even if I only go once during the entire cruise.
Dining room food that doesn't arrive at room temperature.
Slot machines where you can put in $20 and not lose every single pull.
Waitresses in the dining room (not just waiters). I prefer to be served by a woman because they seem more logical in that role. I feel sorry for a guy who works as a waiter for a living.
Clear spaces for walking (no bottlenecks) and fast elevators.