Target audience: Upper Class type people, yacht owners, second home owners, coastal enthusiasts, well-traveled.
There are SO many shells I like...honestly I'm more interested in the design as a whole and not which shell you pick. Also, I use corals and sponges if that helps you any.
As far as the logo...it's so hard to put into words, but here are some thoughts that come to mind:
Classic, simple, edgy, timeless, upscale, clean, not too detailed or frilly, sea grass rugs, botanical, bamboo, rattan, natural, organic
Coastal Living, Crane's stationery, Pottery Barn, Ballard Designs, Nantucket