Springfield XD's in 45 ACP have been available for 3 weeks now and is a good choice for consideration. So are Glocks, or the budget-minded Ruger KP345 with a very slim form-fitting grip.
The best performing 45 auto self defense round I'm aware of is Winchester Ranger T in 45 +P (RA45TP), with manageable recoil and outstanding expansion from sharp talon claws that expand to .95". Penetration averages 15.3".