Right beside your house, once I get the house upgraded I'll put about 2-4 chests inside the house, I craft one right by the fence, beside the little river in Pelican town, beside Lewis' house. For fish, gifts, help wanted quests, etc. In the mines right beside the elevator, for food, weapons, etc. Usually later I'll tend to craft one by Leah's cottage, for fish and anything else. Especially when the trout derby is here, so I have a place to store my stuff. Even with a backpack upgrade, it fills up quick. I tend to usually craft one for the Community Center. If I get some items from the Traveling Cart that I need, but can't use in the Community Center yet, I'll put them in the chest. Same thing with the quality crops bundles. If I don't have enough Parsnips (for example), then I'll leave how many gold star Parsnips I do have in the Community Center where the chest is. I'll usually put the chest beside the progress area for the bundles, where the junimo's put the stars.