If this is going to be a plinker, go with the 9mm. It is a much lighter load, cheap ammo, and more importantly . . . far less hand fatigue after 100+ rounds into paper.

However, if this is going to be a multi-use gun . . .plinking, self-defense, conceal, everybody-in-the-house-should-know-how-to-use-it gun . . . then I'd lean towards the .40S&W from Springfield. The XD models are very nice! Becoming very popular with law inforcement. (Though you'll never overtake the Glock). The round is easily handled by small hands (spouse, daughter, etc) and still has plenty of knock-down if needed.
I got my wife one for mothers day last year, and I don't get to shoot it! She is a non-shooter and still wants to make sure and bring it on camping trips and agreed to attend a handgun class with me. So it has all the multi-use gun specs in IMO.