FYI, regarding tips:
The crew that services you usually doesn't get paid by the cruise line (this probably varies among cruise lines, but essentially the ones I've been on all work like this including Carnival, Royal Carribean, and one that ain't around anymore). They work entirely for tips. At the end of your cruise, you're expected to tip each person for the services rendered. The staff generally work like dogs. Sleep and free time are pretty minimal.
Remember, the purpose of the cruise staff is to baby you. You may not need a cabin steward, but unless you specifically tell him to stay out of your room the whole trip, he's gonna do his best to give you a darn clean room and fresh sheets and towels every day. Same goes for your busboy, waiter, head waiter, wine steward, etc. Depending on the length of your trip, "suggested" gratuities can be significant. Between $50 to $100 per staff person per passenger on the cruises I've been on. Remember, this is their only income, and most of them do a great job.