Sardines--sustainable yes healthy yes and can be really good when you're in the mood but not usually fine dining.

Maybe that will change? Grilled fresh ones can be great.

A New School of Thought About Sardines
(via Felix Salmon which is funny)
Intellectually, it's a strong case, but to succeed, the Sardinistas must overcome a big cultural hurdle. Sardines look like fish. And most Americans would rather not be reminded that the meat they eat was once a living creature. "The reason we eat big predators [such as tuna and salmon] is not because they are big predators; it's because they can be cut into steaks," said Alton Brown, host of Food Network's "Good Eats," who attended the Sardinista lunch. "Americans: We're people of the cut, not the carcass."

The Society for Appreciation of the Lowly Tinned Sardine has links to articles and pictures of interesting imported tins (including chocolate sardines) and spreads designed to look gourmet.
Images of vintage California sardine labels.