Lembeh Strait
I visited Lembeh in October 2013, making 22 dives over the course of eight days. All of the rave reviews of the area I had read are fully justified; it really is a macro photographer's paradise. I came to Lembeh with quite a long list of critters that I wanted to see, and our accommodating dive guide found all of them bar one, plus many more besides. Only the mandarin fish eluded us, but I think this was more due to our dive resort being somewhat protective of their dwindling habitat.
Just a sample of the creatures we saw would include seahorses, wunderpus, mimic octopus, blue ringed octopus, rhinopia, harlequin shrimp, flamboyant cuttlefish, many type of frogfish (including hairy) and countless exotic nudibranchs. Every dive was within a 15 minute boat ride from the resort, and there really never was a dull moment, with our dive guide constantly finding us something new to check out. Every single dive was a highlight, but I particularly enjoyed Pantai Parigi, Nudi Falls and Nudi Retreat.
Max depths ranged from 5m to 28m, and the visibility was better than I expected - 10-20m.
Highly recommended to lovers of small critters, and if at least one your party doesn't bring a camera you'll seriously regret it. Don't expect any large pelagic life - the largest fish I saw was a pinnate batfish.
Flight were via Singapore with SilkAir.