My wife picked up 4 mackerel at Diana's today. Think it's the Atlantic variety (if any of you watch the River Cottage series...it's that kind). They were fresh, not frozen. Seasoned with S&P and olive oil and grilled over charcoal. Possibly the best cooked fish I've ever had. The meat was actually sweet. I made a sorrel sauce and it was not necessary.
$3.99/lb, worked out to $9 for the two of us (and kids ate a few bites). Two fish was a bit much, but I ate it all.