Dollar has gained recently against both the Euro and the Pound. It's not plummeting. Rather, it's gaining, at least temporarily. Also, oil prices (irrespective of the dollar) have gone down drastically due to virtual collapse of the futures. It appears that the Saudis were correct back in July when they stated that the market was well satisfied with supply and that prices were being driven up almost exclusively by speculative pricing on futures. That's an effect that works both ways.