For our honeymoon, September 2001, we wanted to do Southern Caribbean and the price on the Destiny was the best. However, this is the ship I actually wanted to go on as I had seen the pics in the brochure and really wanted to see it. It is a beautiful ship, with so much to do. We really enjoyed it. We have also sailed NCL Sky, which now does Southern Caribbean, but when we sailed on the Sky we had picked it because it was recommended as a good ship for teens (because of the sports). Our first cruise was with the Sensation, and we were happy with it.
We had started with choosing the itinerary first and then narrowed down the choices. The other ships we had looked at (just recently agan for southern caribbean), were RCI's beautiful Radiance of the Seas (but a little pricey just yet), and RCI's Adventure of the Seas (we were leary because of the number of people on this ship -- a little scary).
We're in our early 40's, and we just seem to find the people on Carnival to be friendlier. Although, the cruise director and staff on the Sky were great, too. You just have to put yourself into a cruise to enjoy it.
Anyway, best of luck with your decision.