My best friend had her seven bridesmaids dresses made for her recent wedding, for which I was maid of honor (and hence intensely involved in the fabric hunt). The staff at Sew Unique Sewing Center made finally finding the fabric a joy.
The store has an excellent stock of fabrics. They had at least some quantity of each of the different satins we were interested in, so we could see the hand of the fabric and the sheen to it. The staff people gladly helped us go through color cards and identify good potential matches in terms of fabric needs and color wants. Once we had it down to a few colors, the owner of the shop went outside with us to check and see how the colors looked in the sun from the card (it was an outdoor wedding - how clever of her to think of looking at them outside!), and advised us on how colors change when you look at a lot of it at once (as in a dress). She did not, however, try to push my friend into one color or another - which was great! She ordered the fabric over the phone while we were standing there and it arrived very quickly.
My only caveat was that the zippers we ordered did not come in as expected and they didn't let us know about this delay until we were expecting to pick up the zippers. Even then, they were most curteous, and even sent some of the zippers that did arrive to our apartment in Cary via a staff member who lived near us, to save us the half-hour drive each way.
I would highly recommend this fabric store for their selection, expertise, and willingness to special order as needed.