I think Tropicorium probably has the best corals around - the prices aren't the best, however, but I suppose like anywhere, the more you go, the better deals you get.
I've typically been using The Fish Doctors in Ypsilanti as my default LFS
. They have decent prices on livestock and corals. They give punch cards so you get $10 for every $100 you spend.
I'm a fan because I'm now on a 1st name basis and so I get really trustworthy advice, genunine care, and really great discounts on everything. As an example I recently purchased a Lg. (9) headed Duncan, and a large 8-10" Montiporo plate coral and got both for $80.
I will say this, however, their selection of coral certainly leaves room to be desired. They get shipments often, but it seems that the "good stuff" walks out the door very quickly.
They also have some great clams!!!
Depending on what you're looking for they typically have at least one or two worthy of purchase at any one time.