I'd like to point out a little thing I've been doing: The Natura nether furnace (eight cobblestone in a doughnut-pattern) doubles the burn value of whatever fuel it uses (i.e. coal burns for 16 items instead of eight, sticks for one item instead of half an item per stick, etc.), and coal coke normally cooks 16 per item, so coal coke in a nether furnace cooks up a whole half-stack of items.