I hesitate to resurrect this thread and thus attract the scorn of all the anti-gun folks out there, but...
Has anyone mentioned the Ruger LCP? 6+1 shots, .380 ACP, only 9.4oz and $347. Not quite as light as a KelTec or NAA, but then again this is Ruger, not some frightening saturday-night special shop. If I were to be attacked while carrying a KelTec I might just consider throwing the thing at him instead of firing it, for fear of losing my hand.
A .380 is NOT a manstopper, but I figure it'll at least make an attacker pause a moment and rethink things because if nothing else he'll have some 'splainin to do at the ER. If they know that they can't get away with it, they'll go elsewhere. Few confrontations involving guns end in gunfire, after all- usually one only has to menace with the weapon and the criminal flees.
Normally I like revolvers for self-defense, because they NEVER fail to fire, esentially CANNOT jam, and you can leave it loaded for YEARS and not have to worry about the magazine spring failing. However, I can't find one in a decent caliber under 12oz (S&W Mod360PD J-frame .38sp).
Another option is a derringer. Personally, I'd love to find a light 2-shot derringer in .45ACP (presumably it would need a sort of a 2-shot moon clip). Anyone know of one? Bond Arms makes one but it's 21oz! American Derringer will make them for you, at about 15oz. Supposedly their Model 10 is lighter, but I'm not sure by how much.
(Of course, I'm assuming that the question is "protection from 2-legged predators" rather than, for instance, bears.)
P.S. HI ROG !!!