I can see two lists, one purely objective, and one that includes emotion. I love revolvers and 1911s so I can't really see going without either- without that and only going with "need" I would have a different list. I am not a hunter, and I have only made it to the rifle range 2 or 3 times in the past 5-7 years (I used to go a lot more than that in a 6 month period) so a 3 gun list for me shouldn't include anything that can't be shot at an indoor pistol range.
Including my wants (revolver and 1911):
-S&W 1911SC or similar Commander sized alloy 1911. Good for CCW and big and heavy enough for a range gun. The caliber is more than suited for home defense.
-S&W 65LS (3", K-frame, .357mag). See above for advantages.
-A pocket sized gun. I have a S&W 442 that fits that category, but I'd probably sell it for a Kahr PM9 or similar.
Purely objective (no 1911 or revolver requirements):
-Full sized service pistol or revolver in a major caliber (.38spl, .357mag, 9mm, .40 or .45ACP). Since this would be the main HD gun I'd prefer .38spl, .357mag (loaded with .38spl or a lighter magnum load) or .45ACP.
-Compact CCW pistol (4" barrel or shorter, 28oz or lighter) or subcompact CCW pistol (3-3 1/2" barrel, 24oz or lighter).
-Pocket gun.
*A larger compact gun (a 4" barrel, ~28oz) instead of a subcompact as a CCW could double as the range/HD gun opening up a spot for a carbine (I'd prefer a .357mag lever rifle) or shotgun for home defense. A subcompact could make the need for a pocket gun a bit less important, again allowing the HD long-gun. Similarly, instead of the HD long-gun I may go with a .22 pistol or rifle instead of the home defense long-gun. So, my list is flexible.