Could someone tell me the best place to keep my camera? Does it need to stay in a case, can I just leave it on a shelf? I noticed that right after I bought it, the screws on the very top became rusty, can I ignore that or does that cause problems.
These may sound stupid but I have reasons for asking, thanks.

I guess your climate is an important consideration. In a dry warm climate the shelf probably is OK, but no matter how good your housekeeping the camera will get dusty. The usual precaution is to keep cameras in a case with desiccant (silica gel), and in any event a case is better for transporting a camera.

EDIT: your area isn't low humidity, so I recommend a case + gel.