I'm not going to win any quantity competitions, but I have the materials to make a couple hundred rounds for everything I own on hand. Lead, primers, an assortment of powders, molds, dies, lube and cases. And all the tools I need to reload them.
I'm still hunting for the perfect load for them, though, so I haven't yet sat down and loaded up all the cases I have. Getting close. My loose goal is to have 1000 cases for each caliber and the supplies to load them all at least a couple times. I doubt I'd ever have them all loaded since I tend to shoot at least some of them.

I'd also like to have a stock of supplies on hand to reload stuff for others, too. I don't shoot .223 or 7.62x39 but I have friends who do.
One thing I think about every so often is "how much of this crap can I carry?"
For the most part I'm not worried about carrying it, but part of me is thinking about SHTF scenarios. 10,000 rounds does me no good since I can only realistically carry 2 - 300 or so and still have enough space and weight left over to carry the rest of the stuff I might need. Same with the whole safe full of neato toys: which one would I take, what conditions would dictate that I leave, how much ammo, how to carry it, etc.
Keeps my mind busy while I'm washing the dishes.
Mostly I just want to stock up on stuff for the same reason I stock up on food and other survival basics: everything comes from at least 2000 miles away so having a decent supply on hand is just prudent and economical. And since the ships and planes that bring everything all run on petroleum even if there are no supply interruptions... its simply not going to get cheaper. Ever.