I think the best place in the word in terms of value would be the internet. KEH, RFF, eBay. Unless your meaning Brick and Mortar. Then from what Ive seen, I guess it would be Japan. Many of their stores seem to have reasonable prices. There are less and less stores in NYC that sell quality used gear. Adorama has a nice selection of stuff on display. They have a pretty large selection of used gear, but only display the good stuff. Photovillage has some nice stuff to browse on their walls as well. B&H doesnt really display much of anything nice. Just sellable consumer grade stuff. I havent been in a NYC photo store that has much of a used department anymore, a lot of them are clearing their used gear out to make run for more sellable consumer stuff. I would say HK would have the least value, but their stores seem to have very pretty things.