Hey a security system is a great tool to let you know if somebody has broken in, the problem is what if they decide not to leave, then what do you do.
I have smoke detectors in my house, does that mean I shouldn't have fire extinguishers?
Take the following for what it is worth because I am one of the boards resident SIG-O-HOLICS.
For defensive purposes I like guns that are point and click. No external safeties, no smart guns, no locks etc. I also like having the ability to second strike the bullet if for some reason it doesn't go bang the first time.
Glocks are great guns but I don't like how light the trigger is. Not a bash just a personal preference. I think they require a little more training and a little more care in their use.
SIGs have quite a few things that I like.
They are extremely accurate.
They are the most reliable semi-autos I have ever used.
They have a decocker so I can carry in double action.
The first trigger pull is heavy enough to alleviate my fears of too light a trigger.
Although heavy they have smooth triggers by in large.
They hold their value reasonbly well.
They fit me well. I like the control layout.
Easiest Semi-Auto to field strip and clean IMO.
Safest semi-auto to field strip and clean as the slide must be locked back to break down.
Now the downsides are.
Price
Long trigger reset so they cannot be shot quite as fast as say a Glock or Walther P99
Tend to have a higher bore axis so getting back on target fast is tough for some people.
Basically if I were looking for a good all around home defense/carry gun I would go either SIG 228 in 9mm, SIG 229 in .40 or .357 SIG or a nice Double Action .357 revolver with say a 4 inch barrel, Ruger, Smith etc.
Both guns are reliable to a fault, easy to use as they are simply of the pull the trigger gun go bang variety, safe as both have heavy first shot or all shots trigger pulls, accurate, easy to clean and maintain.
Remember I am a SIG guy so take what I have to say with a grain of salt. Any of the following companies also produce superior products and runt he price spectrum from very inexpensive to second mortgage.
HK Bring your checkbook and two forms of ID
Smith and Wesson (Don't like the semi's because of magazine disconnect "FEATURE"
Ruger very good gun for the money.
CZ probably a better gun for the money.
Walther, get the ones with the German proof marks.
Glock
Kimber I am not a 1911 for carry kind of guy but some good stuff here.
Sprinfield The XD is a fine little pistol and out Glocks Glock in IMO.
and so on.
Just do a little research and make sure you are buying from a reputable company and you are comfortable with the manual of arms and you will be fine.
Just because the finest combat handguns in the world are made by SIG, don't feel bad for buying one of the inferior guns I have listed above.
Chris