My choice would be the Eastern Caribbean on Carnival. Each cruise has it's own personality but the Caribbean is always a favorite. You will find deck parties on NCL (weather permiting) but no singing waiters.
8 Norwegian: Sky, Jewel, Dawn, Epic, Pearl, Breakaway, Getaway, Escape
9 Windjammer: S/V Legacy X3, S/V Polynesia, S/V Caledonia, S/V Diamant, S/V Sagitta X2 S/V Mandalay