i would say, choose a theme just for that space and work around it! for example: maybe "asian" theme! paint the back wall RED or ORANGE, have a piece of buddha statue on the top most rack, you can use one shelve to just hold books with some decorative book ends, and instead of the chair, you can use the asian trunck boxes (if you google for asian trunks, you can see what i am talking about! - look for square boxes), this way, you can also tuck those boxes under the desk/shelf when not in use and the trunk could also be a storage for your files - you can also place a floor vase with some bamboo sticks - the asian theme would really work here as your wood is black/brown this would also turn out to be a peaceful writing space - enjoy!

I agree with Dytecture about using (and matching) the red for the accent wall. And I would strongly discourage using yellow--mostly because bright yellow and bright red in the same visual field remind too many people (including me) of the ubiquitous McDonald's colors.

great . will do that . I have always seen it with square tiles , not with rectangular tiles . .

that is what i have added if you can see the pic above.. want some suggestions on partition that i can use between dining and sitting