Houzz is the new way to design your home.
basement living space
tv and fireplace on different walls?
love that ottoman!
I like the color of the floor.
lots of storage but open shelving might be a problem collecting dust?
maybe some open and some closed but eliminate the fireplace and instead have closed cabinets.
adjustable shelving would probably be a better idea
not necessarily freestanding shelves but shelves for books and shelves for decorative baskets filled with "stuff"
only if you wanted to enclose washer and dryer for looks
combination shelves and cabinets
is there room to move the sofa out and put a book case on the wall behind the sofa? The L shape takes up too much room though, just on the wall behind?
actually, how about Ikea shelving? That way you can move or change with minimal cost. I think they have a wide variety to choose from and much less expensive than built in. Like the ones similar to what you have in your office now?
Praga Wardrobe System
You might want to get a bid on a custom closet design. Have someone come in, tell them what needs to be stored in closet and let them design it. If it's too expensive you can always use some of the ideas and do it yourself?
Don't forget to add plenty of electrical outlets throughout the basement including the laundry room or counter by the refrigerator. Never know what needs to be plugged in. Add them now while the cost is less.