Built in bookshelves down both sides?

A small library room sounds good. The thin wall looks like an after thought, i.e. probaly not load bearing so might be removable. Also, is there a reason why the ceiling height is low

How are you fixed for storage/closets? I'm envisioning built-in cubby/closets on either side for shoes, sweaters, etc. Sliding doors will keep them dust free and out of sight. This prefab storage happens to be in a garage, but is shallow and useful. I would inside mount a roman shade on the window to keep the rad clear yet add some color and pattern. Add texture here with a nice rug on the floor. All you'll see from the bedroom is the ends of the built-ins, the rug and window treatment - could be a good looking solution for your little dilemma.

If the wall is non load bearing than built-in shelves

Shelving on both sides, a floor lamp in corner, roman blind, wallpaper for impact and a single matress on the floor filled with pillows - just pull out from the radiator. [houzz=]

Wow ~ thanks everyone! Here is what I know about the space so far: the walls are against the slanted roof or exterior of house so we can't go into them. The ceiling is directly under the roof (I'll never understand why they didn't originally build a vaulted ceiling with the dormer).

And, we could definitely use more storage! Love the idea of sliding doors to hide stuff!

Not understanding sliding doors. Don't you need to keep it open since the heater is in the nook?

I'm imagining low hidden storage with sliding doors on the sides perpendicular to the window wall. Then maybe a new radiator front with a deeper ledge. The side storage areas could be as high as the radiator ledge and then slightly shallower shelves (maybe 2 on each side) on top. Maybe some triangular corner shelves too?

Whoa ~ fantastic point about fire danger!! Totally put my need for design and storage ahead of safety... Thanks for catching that!! :-)

It comes with being married to a firefighter for almost 25 years....

You can still do the built-ins, but on the rad end just make it upper cabs to the ceiling for items you rarely need to access and keep the ends ends open below to accommodate the heat.

And is that an outlet back in the corner? Hmm... What about those very narrow Ikea folding shoe storage units on each side? And narrow baskets on top of them to make use of the space above? Belts, scarves, jewelry could be stored in the baskets.