not using a new battery

I've just bought a new laptop and had an idea. I got used to using the previous one plugged in, because its battery was totally useless. So I thought why not do the same with the new one.

It is a desktop size machine, so I won't be taking it anywhere in the foreseeable future. Even in the room I don't mind having it plugged. My question is: would the battery be stored better for some time I might need it if
a) I don't charge it at all,
b) I charge it fully and store it or
c) charge it and make use of it from time to time.

So far, I did not take it out of the box. It came from a reputable store, but was in the box with cables and leaflets, not sealed in plastic. I'm wondering if it was used when the OS was installed.
I know li-ion batteries can be destroyed if let empty for a long time, on the other hand I assume the box could have stayed in the store deposit for months so it shouldn't be a problem.