I usually but the official TDF packs from W H Smiths. I'm don't know if it's the best, suppose it depends what content you're looking for, and at £10 it's not the cheapest. But includes a big map, DVD and lots of glossy pics, and I don't buy cycling magazine that often, so £10 once a year is not that expensive. This years is due out on June 3rd - see
Here.