Extended plinking of cans with a .454 Casull will be very expensive not to mention hard on the ears and nervous system. New ammo costs about $1 per round. If you reload, maybe you can cut that in half but it will never be my idea of a plinking round.
The .45 Colt is sweet shooting but it is too expensive for me to contemplate extended plinking sessions with it on a regular basis.
My idea of versatility is based on living in the midwest where .357 magnum has proven to be effective against all threats and all wild game in the area. Occasional plinking with .38 special can be affordable for the average working person. So I would go with a four inch .357 magnum such as Ruger GP100 or the new four inch SP101. The Smith & Wesson 65, 66, 627 or 327 would also be top picks.
Perhaps a better concept is the idea of a versatile battery of two to three handguns and two to three long guns.
When I plink, I like to feel free to shoot 200 or 300 rounds without feeling much pain financially or physically. The .22 LR or .22 WMR are the only rounds that I really consider for serious plinking. The 9mm can also be a cost effective plinking round but not effective or legal as a deer hunting round. Every other caliber makes me think too hard about squeezing off two hundred rounds at cans and paper targets.
If I was spending much time in an area where I felt the need for protection from big, mean animals like moose, grizzly or mountain lions, then I would carry a 4" .44 magnum or .357 magnum concealed and a long gun such as a 12 gauge shotgun or .45-70 lever action rifle. If you really feel threatened, go for the long gun first. The self defense hand gun is a weapon of last resort whether .454 Casull or .22 LR.
Use at your own risk. Past performance is not a guarantee of future results. This could lead to serious injury or death. Void where prohibited. For entertainment purposes only. Cheer up. There is a chance that my info could actually be helpful.