HI Scotty,
I recently visited in Sept...and I have to say I'm jealous, I definetly have to go back this year.
Anyway, I had many people tell me to ensure that I dove the North shore. Their reasoning was that I would see larger critters there.
So, of course, that is exactly what I did. Amazing and Beautiful would be my description. On the first day I saw 6 large turtles, 5 Eagle Rays, tons of Cudas and a Nurse Shark under a reef ledge (sing to the tune of the Twelve Days of Christmas). It only got better from there!
I used FishEye (suggested by the same people) and they were great, most trips we had 5-8 people and 2 DM's in the water with us pointing out the highlights. They gave as much or as little guidance as was requested.
http://fisheye.com/
From what I heard while I was there, there really aren't any bad ops on the island.
Whatever you do, enjoy...and don't forget to give us a trip report when you get home.
Check out Lone Star (in front of the Hyatt I think) for those nights when you want a cheap and good meal.
Jeff