Speaking as a former USMC rifle & pistol coach, range record-setter and current gun owner, I'd concur with your choice of the .22 for a first caliber pistol and would add a proviso not to over-spend (you'll gain opinions as you gain practice & will soon want a different, more personally suitable pistol). For home defense there's really no doubt but what a short-barreled shotgun or (my choice) a .45 Colt Automatic Pistol is most preferred. Every burglar on the planet knows the sound of those rounds ramming home to the chamber, and 9 out of 10 turns tail. And never forget: that pistol is ALWAYS LOADED.
Parsiphal
Wow, averaging two replies per minute so far! Guess this is a pretty good audience for my question overall - thanks everyone! (Did I mention I love FR? :-)
Several folks have mentioned shotguns; I can see that angle for home security, but it's not really what I had in mind to start out with. Is this thing even legal?
I realize revolvers are simpler, but I'm not intimidated by the mechanics of a simple blow-back semi-auto; I'm pretty mechanically inclined and I don't think I'd have any trouble breaking it down. Actually, the fascinating mechanics of semi-autos are part of their appeal to me, silly as that may sound.
I know a .22 isn't much good for personal defense, but it's still better than a Louisville Slugger or a kitchen knife, no?
The Beretta looks good at $310 for the 6" barrel version... I'll also look more closely at the Ruger and Walther 22s. Maybe a Colt 45 or 1911 clone down the road...