For me it is not just the caliber, but the type of firearm or value / collectability.
I have 4 .22 rifles, 3 .22 handguns. 3 are chambered for S,L and LR.
The rifles are a single shot bolt, tube mag pump and tube mag semi. The handguns are a target auto, compact auto and a SA revolver.
I will soon be acquiring a .357 revolver and lever action rifle.