Go for the best price/cabin/itinerary arrangement. There is little or no difference in weather once in the tropics.
RCCL Independence 4/4/09 - Revenge of the JUGS
Carnival Liberty 3/25/07 - "Spring Break" J.U.G.s (Just Us Girls) Cruise - plus my kids
Carnival Liberty 11/20/05 "I ain't cookin' Thanksgiving dinner" Cruise
NCL Norway - "I'm Pregnant with a 1-year-old" Cruise
Carnival Destiny 6/28/98 - "Honeymoon from Hell" Cruise
Royal Caribbean - 1988 - "Ex-Husband" Cruise