http://www.mauiinfosource.com/Maui%2...g_map_main.htm
Places I've been...
http://www.flickr.com/photos/rossmct...7627931218725/
-Olowalu / mile marker 14 south of Lahania, shallow reef, lots of variety of fish and coral.
-Ulua beach in south Wailea lots of convict tangs, turtles, urchines
-Sugar Beach tons of turtles and Manta rays. Open water at this beach so stay out when water is cloudy.
-Black rock lots of fish, lots of people.
-Molokini is worth it simply because of the sure quantity of corals and triggers that one can see at a single time. Go early since the sea gets rough later in the day. If you extremely lucky a whale shark may come in for a visit
I went to the Maui Dive Shop in south Kihei since its the closest departure point to molokini. The boats that leave from Lahania have the same duration trip, but half of it is spent traveling.
If you go Dec - April, its calfing season for whales. I highly recommend
http://www.aliinuimaui.com/maui-whale-watch.htm. The staff is far more knowledgable and informative than the other tours. (our guide was also a biologist or similar from the ocean center)
From what I've heard from several sources don't waste your time on the "submarines" they travel the same path out in the sea and a diver shows off dead sea shells, and not much more.
If out snorkeling during the above months, make sure to listen for whales. you can hear there calls for miles.
Hope this helps,