I've got a stack of 50 cal surplus ammo cans. I'd have to count them, but I'd say I have about a dozen, maybe a few more. Not nearly as many cans, total, as rondog has!
I have one or two 30 cal cans, and one larger can that looks about the size of the one on rondogs top, left shelf.
They seal well, stack well, are sturdy as heck, and hold decent amounts of ammo without getting excessively heavy, though a full can is still a bit of weight. And I've NEVER had a handle even come close to failing on one of these. Can't say that for the plastic versions.
I've got them labeled by caliber and have some cans also dedicated to empty brass, also labeled.
Ammo is stored inside either in boxes or bags. The only time I ever had loose ammo stored in one was when I bought some bulk 9mm from Georgia Arms years ago. If I buy ammo like that nowadays, I'll bag them up in convenient bags of 50 or 100 rounds using Ziploc freezer bags and then store them in the can. This way I can grab what I need in convenient amounts and drop it in my "Range" can with whatever else I plan on shooting and load the car up.