Man, that's one hell of a post, thank you a TON for the wonderful advice....
I went with the 9mm because, after hearing a bunch of local shop owners tell me that .45 was the only way to go because 9mm was not "powerful enough to stop an intruder", and than comparing prices of everything having to do with .45 vs. 9mm, I thought it was more of a sales pitch than anything. Personally, I know that living in a gated community I'll probably never pull the gun for home use, meaning that most all of the time will be range time. The 9mm is significantly less expensive across the board to learn on, and if someone one day is stupid enough to break into my house, I doubt that they will be able to walk through 10 rounds of 9mm.
My thinking is this: It's more cost effective to learn how to be a solid shot with a 9mm. I can use the extra money in cost difference between 9mm and .45 to take classes and get in range time so that if a situation occurs, I won't NEED the .45 because I'll be a solid shot with a 9mm.
With 2~3 rounds of 9mm JHP with good shot placement will stop most of an assailant. 9mm is still good. You don't have to go absolutelly for the .45. The dealers you spoke can be fit into one of those debators always appear in the forum, always talking about what's the perfect caliber for a pistol.
LAPD (Los Angeles Police Dpt.), NYPD (New York Poice Dpt.) and U.S. Army use 9mm. Get it?
And you said you are going for the training. This will maximize your ability to protect yourself. Ask your instructor, if proper use of 9mm is good. I am certain he will agree with you.
.45 would be a good choice, because it has a fantastic stopping power. Any big guy with a thick winter jacket would get knocked down by a single shot in the chest.
But if you are a beginner in firearms, then yes, 9mm is still fine. It all depends on the person, but at first, shooting .45 will give the shooter big stress, because of the powerful recoil (although USP 45 is known to be one of the most comfortable .45 caliber pistols to shoot.).
And, I honestly think .45 is little bit out of practicality, in real shooting situation. Since its recoil is powerful, it's difficult to shoot the gun in double tap (shooting two rounds at one instance) or multiple shots, and many of the gun fights are not finished with a few rounds being fired.
Speak to any experiences law enforcement officers or soldiers who have had a pistol fire fight, and they'll tell it's the both side - you and your enemy- shooting plenty of rounds, creating a hale of bullets flying to each other, while both sides moving around and hiding behind a cover. It's not like the enemy is standing in open view and say "cheese." Not like regular shooting range experiences.
Unless you have been practicing with firing the .45 for many years, it may be uncomfortable to use when engaging in a fire fight.
Most important thing of all, I was told, is the shot placement. Try to hit the vital organs of the (human) target, like head, heart, rib+lung, etc. In my opinion, when dealing with a mere robber (who is not willing to die in fighting), taking the eye shot is the best; although it will be extremely hard to do that.
If you can successfully do the eye shot, you are not only destroying his eye and make him jump around and scream instantly, but the bullet -from 9mm to up- will continue traveling into the head, so effectively damaging the brain and stop the assailant for good.
And just like you said, with 10 shot of 9mm would take a life away.
One of the good things about the USPf 9mm is, you can shoot more powerful 9mm rounds than the average guns like Beretta M92FS can accept. HK designed the gun to comsume powerful ammutions, so you can use 9mm +p in your USPf (ask about this to your ammo salesman).
And lastly, occationally I heard some bad stories about USP 45, as they jam or shoot with poor accuracy if fired in fast sequence. I think it has to do with the flexibility of the USP's plastic frame design (Glock's plastic frame design is very different from the USP, and that's why Glock never jams) and dual-recoil spring. In other words, I don't recommend USPf in large calibers above 9mm.
Good thing you are living in rich neighborhood. And you have kids... then you can be relaxed, and I think you don't have to chamber load the gun with safety off, as I recommended earlier.
By the way, how many days left 'till you get the gun?
I hope this post keeps you staying excited (I know how you feel!).
