Your pre-paid gratuities will include everyone you will need to tip during the cruise (waiter, assistant waiter, head waiter, cabin steward) with the following exceptions: If the maitre'd performs some exceptional or extra service you may wish to tip him and it is customary to tip anyone who delivers room service to your cabin. A 15% gratuity is automatically included on any bar service or wine purchase - so you do not need to tip for those services. However, if anyone has done an outstanding job that you would like to recognize - you can always tip them a little extra on your own.
And as for your luggage: Actually you will tip the porter that takes your luggage from you curbside - but he is not the person who will be delivering your luggage to your stateroom. He only delivers it to the ship. Often you will not even see your luggage being delivered, it will just show up at your door or inside your cabin sometime after you have gotten onboard.