I tend to agree with Delta in that I think the .380 is a rather underrated caliber by many today, and it certainly should not be either discounted or ignored as a self-defense arm. Granted, there are many arguably more effective calibers out there, including the .45 ACP, that punch bigger holes and impart greater energy transfer than the .380. Yet, if loaded with high performance modern ammunition (I prefer the Federal Hydra-Shok), the .380 gives a damn good account of itself. We must not overlook what John M. Browning was trying to do when he designed the round; i.e., create a reasonably effective caliber that could be chambered in a very small pistol. In appropriate circumstances, I much prefer to carry a .380 Sig P230 than to lug around a two-pound hunk of steel in the form of a 1911 Colt, or the only marginally lighter and smaller, Glock 30, both of which I own.
It is certainly true that many very small "pocket" pistols are available today which chamber the larger 9mm Para round (Kel-Tec, for example), but personally, I find these hard to shoot accurately and quickly, mostly due to their usual DAO systems. With my P230 Sig, however, I can dump 8 rounds of .380 Hyra-Shok into a six inch circle at 30 feet a hell of a lot faster than it takes to tell about it. If that fails to discourage an attack, it's time to call in the Marines!