OK, you already decided - but I want to recommend Bali anyway. It's so beautiful, and the people, the food, the culture are all wonderful.
I wasn't a diver when I went there, but the family that run my LDS just came back from a trip there, and said that the diving was fantastic.
Plus, other than the air fares, it's super cheap.
We're actually going to do that area on our honeymoon!
Bali, Bora Bora, Tahiti etc...