I picked the .40 myself. I've heard to many bad things about the ballistics on the 9mm.
at one time the 9MM was rather anemic but with todays bullets being designed to feed and expand well i would wager that you could not tell the difference in gel of the wound tracks of the 9MM, .40 & .45ACP, i know i couldnt tell the difference, now gel isnt the end all tell all but complaints from police depts using the 9MM concerning its effectiveness have dropped off to next to none with the new 124 and 147 gr stuff.
now if ya like .40s cool, i have no problem with that but if ya think ya are getting way better performance in the .40 vs a 9MM thats just not the case any more, the new ranger/gold dot and golden sabre ammo works.