Maldon being one of the more well-known — there is one special shop in Portland, OR (and Manhattan) called The Meadows that specializes in flaky salt and dangerously delicious high-end chocolates. Their selection of 110 varieties ranges from Fleur de sel, sel gris, flake salts, smoked and flavored salts.
Why high end finishing salt? According to their website, "As a general rule, you get the most from your food - and from your gourmet salt - by using as little salt as possible during cooking, then sprinkling your food with a finishing salt at the end."
I can tell you from personal experience that the vanilla salt we bought was gone in a month's time — I sprinkled it on just about every baked good that came out of our kitchen. We also bought a chocolate flake salt that the woman working at the shop encouraged me to use on pastas and tomato-based dishes. I was skeptical, but she was right. And the rosemary salt is a go-to for everything from morning eggs to grain dishes and pasta salads. Now I can't drive through Portland without making a quick stop. Lucky for those of you who aren't close by, they do a pretty brisk online business, too.