There's a major balancing act that goes into handgun choices. Most people want a carry gun to do two things, be small and light enough that they can go about their day with a minimum of fuss, even with the pistol aboard, and be big enough and potent enough that it'd be worth having around in a gunfight. These two ideas aren't all that friendly toward one another.
You've added a third requirement, that is a handgun that is decent enough to shoot that you can learn on it, in addition to carrying it, and possibly needing it one day.
It seems to me that the ideal gun to carry would be a Kel Tec P32. But, it's hard to shoot well, and not the most potent weapons system around.
The ideal gun to fight with, (barring the obvious choice of a mini-gun, or a 12 guage shotgun) would be a full size, high caliber, high capacity arm, similar to a Springfield XD .45 Tactical. But, that's a big honking critter to tote around, and not that cheap to feed.
The ideal gun to learn with would be a .22 target pistol, like a Ruger MKII. Not much for either carry or potency though.
As a three way compromise, I think that I'd suggest a full size, all steel 9mm. Cheap and easy to shoot, and not that horrible to carry. I'd further suggest the CZ-75 lineup.
~~~Mat
