which one do you like?

i'm not comfortable with either.

i think i'd do built ins under one of them and leave the other alone. if they are opposite each other i'd do built ins under the lower section of each.

the one picture I would remove the small chest the other picture I would move the one chair closer to the round table and take away that tall candle holder looking item...less is more!!

Maybe.... second picture remove the tall potted plant, place a sculpture on either side of the table (and pull the table forward a bit), and put yellow flower arrangement from other side on top of table (removing bowl that is there now). Not sure the yellow is the best for that though, maybe something with some red or orange?

First pic, remove lamp and yellow flowers. Arrange chairs equidistant from table, and add a stack of books (not neatly stacked, rather fanned out from each other) on the table?

I like your clean lines, I think it just needs some tweaking.

Oh, if you worked red into the righthand side via an arrangement, you could tie it in on the left side with at least one spine of a book being a similar red. Use the spine colors to play off each other and add interest. Assuming you like the book stack idea, of course. :-)

Add a round pedestal table with a lamp on it to light a dark corner, then put one chair to the left to balance but not clutter up the space.

I quite like the small low table tall to mid size sculpture and tall plant in the setting as it follows the lines. However,, the table and chairs with large arrangement of flowers in over powering the low scale of that space.. Maybe a low pedestal table with an art object or Colourful glass to add a dash of colour and small scale chair to one side.

Being that the staircase is already symmetrical, have you tried using just one chair on each side and one statue on each side. Position each statue under the highest part of the staircase, not where they are almost touching the ceiling. The yellow flowers should be removed--they are too large. The tall lamp should go as well. Neither seem to go with the look of the chairs and the statue. Like the dark table but not loving the silver table.

Looks as if you have a home with plenty of natural light -- which I like.

One chair under the highest part and one other item might work but the second chair under either is a head bumper. I don't care for this open below steps idea because ... of that; however, you could still create the home office nook.

http://cdn.homedit.com/wp-content/uploads/2012/05/home-office-under-stairs-storage3.jpg

Except that these stairs are specifically designed to be open underneath, I'd have preferred under stair storage:

http://www.awesomeinventions.com/wp-content/uploads/2014/09/understairs-storage-11.jpg

https://s-media-cache-ak0.pinimg.com/236x/c9/52/2c/c9522c4e03b13bd185f0997187b97f7a.jpg

http://cdn.freshome.com/wp-content/uploads/2012/03/stairs-storage-idea-04.jpg

http://thebookcaseco.co.uk/wp-content/uploads/2013/10/made-to-measure-under-stairs-storage-unit-Clapham.jpg

or even using it as a place for a pet house -- built in or not:

http://desmoinesparent.com/wp-content/uploads/2014/06/under-stairs-vacuum.jpg

or child's play house -- built in or not:

http://cdn.goodshomedesign.com/wp-content/uploads/2012/12/space-under-your-staircase.jpg

One table and one other item under the other steps nearest a door could collect keys and cell phones, etc. and just be decorative. More than two items just sitting beneath the stairs begins to look like clutter.

the proportions of the plant are excellent, but unless it's artificial, it will grow and there goes THAT:) the chairs are amazing and I think the suggestion of symmetry has a lot of merit....one on each side...perhaps each with one statue? then break up the symmetry with lamp on 1 side and plant on the other....unless that would drive you bonkers!

The chairs make me cringe...I can imagine banged heads just looking at it. A single chair with a more substantial table - minus the lamp. Another idea would be a chaise lounge or a day bed.

The other side with the sculptures, the set up is almost perfect. The chest could be a bit bigger. Leave the bowl, it is lovely.