I've already got a CVA Scout in .35 Whelen, so I'd keep that. I've also got a Winchester 121 single shot bolt action in 22LR, so I'd keep that one too.
I'd like to add something in between, maybe a 6mm Remington or a .257 Roberts or 6.5x55, maybe in a Ruger #1.
And last would be a Browning 1885 in .30-06, slower powders and heavy bullets in a 28" barrel should be quite a thing.