Any of the three you listed can work out well. Handle them in the gun shop and try to rent some to shoot so you'll know which is right for you. I did exactly that and went with the Glock 22 and 23. They were the right decision for me but maybe not for you, so try out as many guns as you can and you're less likely to make a mistake. Accuracy and reliability are good with all three or you'd hear about it. As far as 9mm vs. 40S&W vs. 45ACP, again try them all out, there are excellent SD loads in each caliber.
The biggest issue with assembling an AR isn't so much getting the parts together right - it's getting the right parts together.
US Army 1966-69, VFW Life Member, Retired Geek