Probably a bit after the fact but thought I would chime in anyway...
Atlantis cruises are great! My partner and I went on the Western Carribean cruise in '03, and it was the best vacation I've been on.
It's hard to describe how great it is to go somewhere and feel totally comfortable about your surroundings. The staff was very accepting...in fact, they look forward to the Atlantis weeks so it's not all senior citizens and families!
You can make the week anything you want...if circuit parties are your thing, they've got 'em...if you like lounging by the pool, or seeing shows, or going on the excursions, it's all there...
We enjoyed it so much that we're taking our 2nd Atlantis cruise this summer -- we're going on the Barcelona to Athens cruise in July...can't wait!