For me buying or otherwise acquiring something just to own it has no attraction whatsoever. Though I find guns endlessly fascinating in lots of their endless varieties if I don't have some type of use for it, actual or perceived, then I'm really not interested in owning it. I've too few resources to be tying up a significant amount in something I just have no need for.
My tastes are rather pedestrian and utilitarian:
-Glock 9mm pistols for defensive use
-Ruger DA wheel guns in .357, .45 Colt or .454 for CCW, general use and hunting
-Ruger 10/22's as my .22 of choice (though a Ruger American recently snuck in)
-AR in 5.56 for defense, CMP, varminting etc
-.357 rifle now that they're legal for deer hunting in Ohio
-A couple 12 gauge shotguns, a short barrel semi-auto for slugs & buck and a O/U for everything else.
I've a decent size safe bought to hold what I own with a bit of room for growth, and as long as I control my penchant for acquiring 10/22's I should be fine.
I have no kids as heirs. Only a best friend, one brother and one nephew who are shooters to leave anything to, so I'm not acquiring to outfit descendants for posterity, only for my use, curiosity and enjoyment. And as a 200 yard range is the longest I have access to, anything too exotic makes no sense.
So how many are enough? Maybe a few more yet, but as I realistically mostly have anything I might need now I'm kinda into wants territory. In that vein, a .45-70 is a rifle I'd love to own.