#4. "As I recall, Bill Claff's numbers indicate..." In response to In response to 0
I know this is hard to believe, but cropping in post may cost you up to half of a stop (I'm going from memory here) of DR. The other thing to bear in mind is that if you know you're going to crop you need about 1 stop less DOF, which likely means 1 stop lower ISO (again increasing DR). Then there's the smaller file and better fps. Adding all of these advantages together, I'd suggest using the DX crop as a deliberate technique and strategy when you know you need the reach.