The best advice you'll recieve is the post by Cruise Fanatic. I work in the industry and there is no one cruise line or destination that suits all people and demographics.
Southern Carib (not as crowded as Eastern/Western), Hawaii is great in the fall and there are a lot of other great choices if the time and budget allow.
Most of the cruise line will add a few perks but don't expect anything too special as most are also currentlt cutting some of these type of perks to be more competitive with pricing. Don't let a bottle of champaigne determine your honeymoon plans.