I have nearly exactly the same layout, except add a door in the upper left corner and replace your bottom wall with wall, wide opening, closet. My room is also longer than yours - it's 18'x18'. I have added Billy bookcases with the half doors and height extensions to either side of the fireplace. It looks good and the extra storage is a godsend. I would definitely integrate a desk into any built-ins you do, like the picture kellyeng posted. Obviously custom built-ins/bookshelves are nicest, but the Billys are fine if you are on a budget. You could buy the short ones and/or cut the Billys down to fit on top of the desk. I have found two layouts that work for my room. Obviously we have different furniture but perhaps reading this will help you. 1) float sofa in front of fireplace, put sofa table with lamp(s) behind sofa, put two upholstered/leather large chairs in front of left window, float loveseat in front of slider on right, put coffee table in front of sofa, place dresser for extra storage on bottom right wall. 2) Float sofa and loveseat in the middle of the room perpendicular to fireplace with coffee table between them. Put the two large chairs south of the sofa & loveseat, angled toward fireplace. Put dresser for extra storage on bottom right wall. My TV is above the fireplace since DH wants it there, but you can easily put yours in the upper corner since you have less furniture. I would recommend that, actually, since the closer you are to the TV the less comfortable it is to look up that high. You really just have to move things around until you are happy - at least for now. The room is awkward, no doubt about it. So, when I get sick of one layout I switch back to the other. I switched back to my Option 2 yesterday. DH laughs at me but hey, moving furniture is cheaper than moving.

So far you seem to be concentrating on cool colors and neutrals, and on cloudy/rainy/snowy days your apartment will seem rather cheerless. Introduce some warms colors, yellow and terracotta, for instance, with pillows and art. Find some very large abstract prints that have warm and cool colors both. The more wall space you can fill up with art that you love the more furnished your apartment will look even when you don't yet have all your furniture. Also, consider tribal rugs like Gabbeh (check esalerugs.com) instead of modern rugs for a more cozy and eclectic feel. You can return these rugs without charge, and you'll be able to pick pillows and other accessories using the colors taken from the rug. Make sure the rug is as large as you can afford because a larger rug will make your living area look larger and more "furnished". Don't forget books, plants and of course art to make your new home look stylish and warm. Try not to use blues and grays too much; that will just make your rooms look cold and forbidding.

you have a good base. all you need are accessories. art. here are similar furniture ideas to yours, but look at the overall room I love something like this w/your white sofa and rug. some nice contrast. and the art and decor items all blend in well or something like this if you need something for the tv

Could you post dimensions for the living and dining room? It looks like the distance from the couch to the TV might be too far for proper viewing. If so, it might be best to float the couch in the room and put the TV console where the previous blue couch was. Also, do you know what size the TV will be?