My husband and I went on a Celebrity Cruise in January, and there was an entire subcruise of observant Jews, operating under the title "Suite Life." They had kosher buffets, ate in subsections of the dining room, etc. Seemed much better than the pre-packaged option that otherwise would have to have been taken. There were places to daven, and we even had a Shabbos elevator that stopped on every floor. I spoke with lots of the women, and they raved about the quality of the food. Their website is www.slkosher.com.
If you have had the meals from the parks it is the same company. I did kosher on a disney cruise a few years ago and the food could have been better.
At dinner every night - you can order the night before.
Also the kitchen is near Parrot cay - so use that dining room for boarding buffet and your food should get to you a little faster.
I was on a Disney Cruise with my wife and two small children last year (January 07) and the Kosher food was great. Of course it is pre-packaged, but the waiters asked us the meal before what we wanted and they had enough selections to keep us happy. The kids meals were pretty good too. I was really impressed when we got to Castaway Cay (Disney's Island), and we went to the bar-b-q and they had our Kosher lunches ready for us and in our hands in a matter of minutes. By the way... outside of the Kosher Food issues which were fine, -- the whole cruise was amazing I would recommend it to anyone. My kids were 2 1/2 and 4 1/2 (both toilet trained which made a difference to their ability to go to the kids clubs)