I love to eat lightly salted fresh tomatoes, so some time ago I undertook trying every type of sea salt I could find (I eliminated commercial Morton type salts right off the bat . . . too much salty "bite" made them have an almost artificial flavor to me). I can't remember what all the brands I tried were, but I remember Sicilian brands, Atlantic brands, Mediterranian brands, a Dead Sea brand, a Great Salt Lake brand, etc. There really were differences, but one salt stood far above the rest in my opinion, and that was Redmond Real Salt, a salt mined from several million year old sea beds that are now buried far underground.
Here's their website: http://www.realsalt.com/
For one thing, it is pinkish in color, and it seems almost moist compared to other salts (though it probably isn't). When I tried it, I tasted a salt which for the first time actually had flavor beyond saltiness; in fact, it is about 1/4 less salty than normal sea salt (IMO), so I always increase the salt measure by 1/4 when I cook with it. I highly recommend trying it if you haven't. Here's an excerpt their website:
"Long before the earth knew pollutants of any kind, a huge, ancient sea covered what is now North America. Pure, natural salt was the main ingredient of this sea, and over millions of years, the water evaporated, leaving the salt in undisturbed deposits. At some point during the earth's Jurassic era, a range of volcanos erupted around the ancient sea bed, sealing the salt with layers of thick volcanic ash, protecting these precious deposits against the pollution that man would eventually introduce into the environment. Near the small town of Redmond, in central Utah, approximately 200 miles south of Salt Lake City, we extract this hand-selected salt from deep within the earth, and bring it to you in its pure, natural state-without any additives, chemicals, or heat processing. . . . RealSalt's unique flecks of color are the result of more than 50 natural trace minerals essential to human health (including natural iodine!)."