8. Delta Air Lines ( DAL) provides air transportation to passengers and cargo. Delta swung to a second-quarter profit of $467 million, or 55 cents a share, as revenue advanced 17% to $8.2 billion. The operating margin jumped from 0.8% to 11%. Delta's stock trades at a forward earnings multiple of 5.3 and a sales multiple of 0.3 -- 78% and 72% discounts to airline industry averages. It's expensive based on book value per share. Of researchers following Delta, 13, or 93%, advocate purchasing its shares and one advises holding them. None suggest selling Delta.