Assumption is you're in the US & on AT&T ...
Depends upon your use case (& AT&T's continuing sub'd upgrades). Nokia McLaren s/b out just before Thanksgiving, but with 3D touch, who knows, could be delayed.
Currently the Lumia 1520 is the best Windows phone offered by AT&T. If the size won't bother you (doesn't bother me, or most, once they have it for a week) go for the Lumia 1520. Advantages are spec'd everywhere, big one is SDcard slot (supports up to 128GB card) & camera w the vibrant 6" screen - don't know about the next iteration.
Will you be able to wait for the next flagship ? You could wind up like that guy ^^^