I'm slowly building up my "arsenal" and have a few questions about storage.  I'm currently keeping everything in a wooden cabinet in my desk (cool, dry, dark).  I'm planning on picking up a few spare military style metal ammo boxes and wondering if it's better to keep the rounds in there boxed or loose, or does it even matter.  I probably have enough to fill up a box worth of 9mm, a box of .22, and a box of 12ga.  I think I could fit more in if they were loose however.  Does it make a difference either way?  

You can probably get more in an ammo can loose, but I prefer to keep everything organized in boxes within the can.  Even in boxes, I can usually get at least 1000rds of 9mm in a .50 can.  Worst case scenario - you have to buy another ammo can or two.