Actually, is it better to have the increased bandwidth or faster timings? That was the second part of the question.
Look at those charts and explanations on all pages carefully. They answered all your questions.
The extra performance by running the memory at 800 is not worth much, unless you are overclocking. The better timings by running the 800 at 667 are worth it in your case possibly. I would compare the timings of both at 667. Then make your choice.