Thanks for the replies.
A number of people have mentioned the Glock 23. I really like this pistol and agree that this might be the perfect handgun for a lot of uses and scenarios. For my money, it may just be the perfect compromise of size, firepower, weight, etc.
But I can't help but think that it is in some ways overshadowed by Glock's other offerings, at least as far as how history will record things. When I think of Glock's contribution what comes to mind is not only that they brought plastic pistols into the mainstream but that they did it with what is probably the king of the wondernines (remember that label?) in the Glock 17.
I realize the way "history will record it" may have little to do with practicality and real life use, but I think it's something fun to consider besides the "if you could only have one SHTF gun" question.
Thanks again.