I keep most of my rifle ammo (7.62x39, .308 and .223) just on the top shelf in my bedroom closet. My hangun stuff is usually out in the garage (with my reloading stuff) with a couple of boxes of defensive stuff in the house.
I really need to stock up though. I need to get a new die so I can make more .223 and when money isnt so tight, I need to buy a couple cases of 7.62x39 and .308. The handgun stuff I can make myself for a lot less than I can buy it. In fact, I just loaded up 250 rounds of 9mm a couple of nights ago. 250rnds went by in about an hour and I was taking my time. Gotta love reloading.
But I do keep some stuff in ammo cans. Just not a lot. Most of it is stacked away, not under lock and key. I do however keep some of the good SD ammo (gold dots, ranger, etc) in one of my gun safes. Just easier to keep it there so it doesnt get mixed up with my other hardball stuff.