My favorite is still the little Topeak handlebar bag
http://www.rei.com/product/735854
It converts to a fanny pack, is just the right size for my camera, wallet and some snacks. It doesn't have a map case, but I've attached a small map case that normally velcros onto the handle bar onto the bag's handle. Works well.

At the time I bought it, there were a bunch of references to it here on other threads.