I generally hate these kinds of questions.....
But, I'll play....
1 pistol and 1 revolver to "keep" for home defense and personal defense?
Ok, first, "keep" means something from the collection I currently own. AND, "keep" also implies that I would be getting rid of the rest of my collection (NOT a happy thought)
Second, where do you make the distinction between "home" and "personal" defense?
Third, "keep for defense", to me, means not doing any other kind of shooting (other than practice).
That being said (and assuming I am understanding your question correctly), what I would keep is
Pistol: My father's Colt Govt model .45ACP (inherited in 2003)
Revolver: Colt Agent .38spl
While I would prefer to keep my Browning BDA .45 over a 1911 for "social" work (it carries better), I choose to keep the gun with family history over the rest.
As to the Agent, its nice, small, light, pocket gun (and the only revolver I have in that class), since you specified "defense". Now, if the question was which revolver I would keep, for ALL uses, if I could only keep one, then my choice would be different. And it would be a tough choice, between 4 guns, two DA and two SA. Rimfire (allowing a centerfire pistol for defense) I would have to choose between a S&W model 17 and a Ruger Super Single Six. After a bit of reflection, I would keep the Ruger, as the S&W is worth more to someone else.
Centerfire, it would be a tossup between a S&W Model 28, and a Ruger Blackhawk (convertible) in .45 caliber (.45 Colt cylinder in the gun). The Smith, because it will handle full .357 Mag loads, my Father had one (and while I don't have his gun, I have one just like his, and because I love N frames when concealed/defensive carry is off the table.
The Blackhawk? Because its fun, accurate, capable of shooting loads matching the .44 Magnum, and in a real pinch, can shoot the same ammo as the Govt model which I'm "keeping" for defense.
It would be a tough call, for me. Which is the main reason I hate the which one to
keep questions. Now, which one I would choose for ...is a different question, one which lets me keep my other guns, for when I choose differently.