Agree with another poster - Lanai hot tubs are great.
Decks 6, 7, 9, and 10 - go all the way to the front of the cabin hallways, and you'll find a door leading out to a forward deck. It can be windy at times but is a great view. Also, go to deck 9 forward at night time, and you can get a great night shot of the side of the ship, This forward deck has a "side area" for viewing.
Take closed toe shoes if you want to try the ropes course.
Ocean Plaza is a good place for music.