Well, I guess it depends....
[b]Transport:[/b]
Sling on back, when I'm either traveling light or packing in the field.
Hard case, when it's just an AR or two and I'm going to the range.
Assault case, when I'm going to the range with a crap load of firearms and want my AR stuff in one place. Assault cases are more field friendly than a hard case. You can sling them on your back and later spread them out on the ground to lay your rifle on without them slip sliding away. In a primative shoot, I always pack the assault case if I'm taking a case at all.
[b]Storage:[/b]
In the safe mainly when not being used or worked on.
On my bench stand for short intervals between working on it.
On the wall gun rack, when it's more than a one day job.
In the case under the bed, when I can't take my eyes off it and want to take it out before I go to bed and play with it. LOL
Overall, I store it with a light coat of oil, always.