Each cruise line has it's own style, an onboard dress code which defines the cruise experience. Here is a brief breakdown of the two predominant styles of cruise...
Informal Cruise Lines
Carnival - Island Cruises - NCL Freestyle Cruises - Ocean Village
Formal / Semi-Formal Cruise Lines
Azamara - Celebrity - Costa - Crystal - Cunard - Fred. Olsen - P&O Cruises - Princess - Royal Caribbean - Swan Hellenic