Ed, theres pleanty of good advice in these posts but I'll add my 2 cents...
I am not apt to leave the house with the 1911 . 45 or the Sig 226 9mm. They are just too big to try to conceal in my opinion. I wouldn't give either of them up but they don't usually fit that situation.
A consideration that might fit both you and your wife might be the S&W Bodyguard (auto) in .380 with an integrated laser. I had one and carried it, but sold it and I regret doing so. There was a hole where that laser was when I pulled the trigger, the gun was light and in my opinion, the caliber and payload were adequate.
Its cousins, the S&W Airweight or S&W Bodyguard (revolvers) mentioned are also great choices for their reliability.
I have a Springfield XD40 subcompact that ups the ante a little more and is very concealable (but a tad heavy if carried in a pocket)
For now my carry gun of choice combines a lot of the traits mentioned above...size, reliability, horsepower and capacity.
The Colt Cobra .38 SP, 6 round snub with a 2" barrel and Hogue monogrip. Light, accurate, reliable and plenty of "just keep movin' ".
Heck, Jack Ruby owned and used one and he wasn't even from the Flint MI area