Brandon Sanderson has plans in place to write many books set in different worlds, but in the same Cosmere. These books include series that have already begun (eg Stormlight Archives, Elantris, Mistborn, and others), and some that have not yet started (eg Aether of Night, Dark One, and Dragonsteel).
What order (if any) should the books be read in? Obviously, books should be read in the proper order within a world, but is there reason to read the books of one world before another?
I do realize that the answer to this question will change an evolve over time as more books are released, but answerers today and in the future should respond according to the best knowledge available to them at the time answered.