Fiji
I had the chance to visit Fiji in early December of 2013, and had a wonderful time diving as well as exploring on land. We stayed on Beqa Island, so the island itself is very rustic, and you can walk into the villages or do some day hikes near by. Diving was primarily done in the morning, and with 6 dives days, we scheduled two of those to be the famous bull shark feeding dive. No regrets!
The reef dives were beautiful, with many soft corals for beautiful reefscapes, and very rich in color and life. For me, the highlight really was the ability to dive with bull sharks. Our trips were organized through Beqa Lagoon Resort, and we were very happy with how professionally they were run. It was a wonderful opportunity to get to see these huge animals up close. Bring a camera ...any kind! You'll definitely want pictures or video!
The weather was warm, in the 80s and water temps were 78-81 during our trip. You can also do some snorkeling and other activities like kayaking or jet skis around the island. We primarily dove in the mornings, came back for lunch and showers and then spent afternoons doing more topside or surface water activities, so Fiji is a destination that is friendly for non-divers as well.
And last but not least, try the Kava, at least once.