I try to be pretty analytical and harshly minimalistic with my gun purchases now. I've bought lots of guns for the reasons you've mentioned, guns for which I had no real use, like SMLEs and AKs and SKSs and big revolvers. I had an M4gery for predeployment training, but it became useless. I have since sold all these guns, though.
I still have an M1 Garand with no earthly use besides "power plinking." There's just something about the feel of the Garand. It's the only gun I own purely for casual, irrelevant fun shooting. I drag it out on Memorial Day along with Old Glory and blast away.
I still have to divest myself of a couple of useless (to me) or redundant guns.