Why is it that more people don't eat sardines (also called herring)? They're one of those great species of fish that has everything going for it: sustainable, widely available, safe from nasty contaminants, and absolutely stuffed with good omega-3 fats (you'll always see sardines appear in the same list as salmon, two of the richest sources of these heart-healthy fats).
In canned sardines, you can usually even eat the delicate bones (you won't even notice them; they get softened during processing), which provide a good dose of calcium, and they're a natural source of vitamin D. I'm on a crusade to get people to try them; they're mild and delicious, good by themselves or on crackers or mixed with eggs or olives or hearty vegetables. I love the ones from Bela-Olhao; wild-caught off the coast of Portugal, these terrific sardines are packed in different flavors: olive oil, lemon, tomato, and cayenne pepper. If you find fresh sardines at your market, take some home and grill them. And keep a couple cans in your pantry; they're a terrific take-along meal. (Do compare labels for sodium and calories; depending on what they're packed in, these amounts can vary wildly.)