which gun to buy?

Things happen in my type of employment in which certain potentially dangerous individuals make at least what might be perceived as credible threats against the safety of myself and my family.  Because of this my wife has asked me to purchase two sidearms, one for me and one for her.  (This also explains the purchase of the large dog with specialized training for the home.)

As a bit of practical advice....get a short barreled pump-action shotgun for your home (remington 870 or equv.) load it with 3" number 4 shot turkey loads. Practice with it a good bit.

You can't go wrong with any of your chioces for handguns (why not a Glock?) I am partial to the H&K's though.

Ah, Sigs, excellent choice.....

Nope, not in love with .40 at all.  My first thought was I wanted to avoid a 9mm.  Our local LEO's are switching to .40 as are the Feds. (I think).  So my natural thought went to a .40.  I've also considered a .45, but for some reason (nothing concrete) I really didn't look into .45s.

sizewise how is a 1911 going to compare to a full size model of the three .40's  I listed? (I could go with the H&K SOCAM...just kiding

As a rehabilitating gun collector and former IDPA/IPSC/3-Gun competitor...I've pretty much owned and shot every pistol out there in general circulation; Beretta, SIG Sauer, Glock, Colt, Kimber, Springfield, Steyr, Ruger, Smith & Wesson, etc.

When I downsized my collection of probably 20-30 pistols, I kept only my 1911's and Glocks. I haven't looked back, or desired to own any other pistols since.

I would take a serious look at the Glock models in .40 (22/23/27). They are simple to operate, reliable, accurate, incredibly durable and corrosion resistant.

There's nothing wrong with any of the other brands mentioned above--HK's are first class, but their USP have big and blocky grips for me--its just that a Glock IMO makes a pistol to fit just about any individual's self-defense requirements without breaking the bank.

I don't recall if its been mentioned, but get yourself some first class training. Then, practice with a purpose and regularly.

Invest in a combat-type flashlight (i.e. Surefire, Gladius, etc.) and practice shooting while clutching the light in your preferred hold. A real self-defense shooting is likely to happen in low-light. And with the axiom of never shoot at anything you can't id, you'll need to learn to apply illumination on your target.

If you're truly serious about self-defense, set aside the funds to take one of the self-defense classes (a la Gunsite). Shooting for fun is one thing, shooting under pressure or in low-light is another.

Edit:  The only "pressure" I've shot under is competition (and self-defense shooting courses)--which is/are admittedly even a poor substitute for the real thing.  I've never "seen the elephant" and hope never to. 

WOW! ...and I worry about locking the dead bolt. I hope you get to retire early, win the lottery, or something!