Bali
I loved diving Bali and found it to be one of the most diverse areas. It is my favorite dive location in the world.
I lived in Bali in 2008 and worked as a dive instructor. I was able to see many of the dive spots in Bali and live the dream. :) The scuba diving was cheap and plentiful, the locals were friendly and helpful, and the food is delicious! You have macro, you have large, you have drift dives and you have muck dives. You can easily get to wrecks to enjoy some great wreck diving, get deep, and dive shallow. There's truly something for every scuba diver and every level.
The water is warm (for the most part) but there are dive sites in Bali that are have cold currents flowing in from the Indian Ocean. Don't forget you are diving near one of the deepest trenches in the world. I mostly dove in my 2.5mm shorty or a 5mm full for the colder dive spots in Bali (Crystal Bay, Manta Point).
I recommend getting up to Tulamben. There you can dive the USAT Liberty and stay the night at the Paradise Hotel. This allows for night dives on the wreck and on their house reef. Other areas that are a must are Crystal Bay, Manta Point, or really anywhere around the Nusa Penida islands. The creatures you'll see are plentiful! We're talking nudis, mantas, sharks, all sorts of tropical fish (lionfish, triggerfish, parrotfish, etc). You can see large and small while diving in Bali.
My biggest (and only) gripe about Bali was the trash in the water. It's sad but there is a lot of rubbish in the water (cigarette butts, water bottles, fabric, etc). The Balinese do several religious ceremonies that involve temples being placed into the water. Most of these are made form plants and wrapped in fabric (which ends up in the ocean). The divers and dive operators are really aware of this situation and do much to clean up the areas but it's still a problem.
Some fun topside activities are going into Ubud for a relaxing escape from the bigger cities. You can go for a hike or rice patty walk, see religious dances, visit temples, or hit up a spa for a massage and milk flower bath. Be forewarned, the Balinese are not embarrassed by nudity and in the spas will have you strip down right there in front of them for your massage, bath, scrub, etc. But it's worth it! Or head to Kuta for surfing, club action and shopping.
