Aqaba is a 1.5 days stopover. Petra is a full day. Dead Sea is a full day. I would recommend PETRA. You do have time to do half day Wadi Rum 4x4, which is great fun.
For anybody who does not know, 'Celebration' is identical to 'Spirit'. They belonged to Holland America (many, many years ago).
As many have said, most ports are industrial, so you really need to do the ships excusrions, which are expensive but value for money. They are also VERY long days.
This itineray is not really for small children on a small ship (little in the fun department). It is also not for those who wish to stay on board and enjoy the 'view'. TAKE A LOOK AT MY CRUISE REVIEW AND PHOTOGRAPHS (31 pictures) BOTH TITLED THOMSON 'SPIRIT' RED SEA MAGIC MARCH 2009 BY GREENSLADE. It will give you an idea what to expect.
You only get to do one trip we did petra it was a long day but well worth it.
After the Petra trip, you need the next day to recover! Up at 5.00am, it is a very full day as well as physical. Unless you are very fit, think twice about going all the way down to the museum. It is quite a climb back up and can be very hot. The bottom line is that there is no time to go to the Dead Sea which is a pity.