In my humble opinon.
1. A quality 22 of some sort, with big easy to see sights. Cheap trigger time, fundamentals, accurate. Say a Ruger Single Six/Ten for revolver buffs, one of the Ruger Mark somethings in semi auto flavor. My choices for both, Ruger Single Six and Smith and Wesson 422.
2. A medium sized mid-bore of some sort. Less offensive trigger time, reasonably powerful and handy. Say a 3-4 inch barreled 38/357 or mid sized 9mm. My choices here, Smith and Wesson Model 19 and Glock 19
3. A shortish barreled large bore. Something long enough to shoot easily, yet not something that resembles a buntline. Powerful enough for serious business, but not a wrist breaker. In this category, I think the revolver shines due to the multiple power levels. From mouse fart loads to bear busters. For me, a 4 inch 629 will handle anything that needs handlin, while being handy enough to tote around. Course I'm a big guy and spend most of my time in the boontoolies. When I still owned a Glock 20, I used that a ton. Heavy lead Double Taps mostly, blazers to plink.