I have to say i like to split my LFS up.
Aquarium Adventure Carle Place -I Don't like the non personal feeling you get when you walk in there. Been there at least 50 times and they still don't recognize me and i've spent a lot of money there including a 29 gallon and a 125 gallon tank with stands and all the supporting equipment. I find they have better and more stock of equipment. I go there to get all my equipment, salts, test kits, filters, foods, etc etc.
Tropical Island Aquarium in Deer Park - Absolutely right about their corals. They have a beautiful display of corals and frags and they are very friendly. Not a giant selection of fish although they do have some incredible lighting set ups and a decent selection of equipment for such a small store. I will definitely use them for corals.
Tropical Showcase Hicksville - I deal with Gene quite often. He's very reasonable and in my opinion has the best pre-cured live rock i've ever seen. All the rock i've bought from him have had the most life on it and the best algae unlike Aquarium Adventure which the rock cured in my tank for almost 2 months just started growing algae. His fish never have any spots or discoloration on them, but i do agree with other people that he does keep them in small tanks. I can try to talk to him about offering discounts for MR members. On top of all this he's honest and wouldn't sell me fish or corals or anything until he was sure my tank was fully ready.
Those are my experiences at these places but i haven't really been anywhere else yet.