I turned one into a little room for my dog once, with a half door on the front. It could be a little reading nook for a young kid also.

In DH’s childhood home, that was the dog’s night nook. In my condo, I kept my luggage back there, and the front was for coats. In my townhouse, same thing.

Got kids?

In our old house we put momento storage in the way back and holiday storage in bins in in front of it an then off season coats and boots in front of that. It was organized but stuffed.

Can you make a separate door from the side for the backmost part? We had a long closet under the stairs, at least half of which was inaccessible, and during a metastisizing kitchen reno, we subdivided that closet into several sections, including a pull-out drawer for the lowest section. All immediately useful! :)

I LOVE acm's solution!

What is your biggest storage need? Perhaps, since you just moved in, you can wait until you need a place for something. No need to fill up space just because it's there.

OTOH, I have under stair storage. I use it for seasonal things - artificial Christmas tree, hunting clothes - things that are in tubs and can be easily pulled out to get what we need, but only needs to be accessed a few times a year.

If this is "prime real estate" in your home, you may want to use it for everyday use - vacuum cleaner, sports equipment, etc.

Only you know what your needs are, and how the space relates to the house. Good luck, and let us know what you decide!