Without doubt, Wakatobi in Indonesia. We went back a THIRD time last November. Did 18 days, seven on the Pelagian live-aboard and 11 at the resort. Critters galore (mostly the small kind, not for big stuff). Pristine reefs. Great dive operation. Did 52 dives during the trip... averaging 70+ minutes each. For photos, see:
Wakatobi Dive Resort - October 2007 - a photoset on Flickr