Your sailing in August huh? Are you on the Eastern or Western Caribbean itenerary? I am sailing with my wife and some friends on the Eastern Sailing on the 21st. I agree with you, Celebrity is a great cruise line choice, have sailed twice on Century, and have the mercuy to mexico scheduled for Feb 2005.
If you want a 7 day party sail on Carnival, their name is synonomous with what they offer, a carnival.
Celebrity's name as well does it justice. You feel like a celebrity, with a sophistication and class usually associated with the celebrity genre.