You could perhaps do with brighter pops of colors in the throw pillows (and if you end up not liking the pillows, you can change them out)--but I feel like you could use more lighting. Maybe floor lamps or table lamps. There is a lot of great natural lighting coming from the windows, but what about when it gets dark? Let us know if you'd like more pointers or product recommendations.

this room lacks color. Paint the wall with something bright like creamy yellow or ivory or light shade of green, It looks dark so you need llighting. put colorful pillows , it would be nice to have a flower arrangement on the table ,

In my opinion, there is not enough color or pattern in the room. I would use a brighter color and pattern on the drapes and the rug. Also I would use larger throw pillows on the couch with a large pattern - perhaps one of your colors mixed with cream. Check out some of the pillows at Z Gallerie for inspiration - they frequently feature large geometric prints.

Thank you, house 1985. The walls were ivory, as all walls in the house. I've just painted grey in the living room, in order to be in the 60-30-10 color scheme that i was thinking about. The flowers on the table would be wonderful. The challenge here is to make the room and child friendly. I have 2 little boys, they would hurt the flower every day. I was thinking to put on round high edges chartreuse tray on the table, for the little snacks or water that we serve in the living room. Not sure what kind of furniture to choose for the wall with tv on. I was thinking at something like in the picture. And I would make the coffee table a little lower and changing it's color to be darker, wenge. http://www.ikea.com/ro/ro/images/products/hemnes-comoda-tv__0176602_PE329457_S4.JPG

Added comment: This is more about scale than color. I need to leave but I will provide more feedback later today. Before I wrote: Lose the tiny green round rug. Take down those two framed things on the wall. Toss the dying plant. Hide the remote-put it in a colored box. Get some color with brighter pillows, large artwork on wall. Put some color on the table-maybe a silver tray with green apples. Stand back and look again. You probably need to edit some of the small stuff on your TV stand. The 3rd photo did not follow. Same room?

Singmaster, yes, was the same room before transformation. Thanks for the tips :)

You've made a terrific start. I think you need a little tweaking here, enough to brighten the room a bit. I don't quite understand the TV wall, but I'm gonna take a crack at your room anyway. I shall return.

The rug: http://plushrugs.com/nuloom/barcelona/tatiana/chartreuse/
The ottoman in Klein Wheatgrass: http://www.thrivefurniture.com/taylor-ottoman/

Let me start over again.
This is about scale rather than color. You are a big grey sofa, a coffee table and dark cabinets, so a good start.
Plump up your cushions.
First you need to think about color. Do you want to punch it up with color? Or keep it monochrome? Or change it out during seasons, say bring on bright green during the Spring, then change out to Red (or Purple or Dark Green) during the Holidays and then monochrome when during the fall or when you want a more formal look and feel. I do this. It keeps things lively and you can do it inexpensively with pillows, throws & accessories.
If you want to keep it monochrome, you do that by adding light and medium gray pillows and throw. Get rid of what you have on the wall and make that another focal point. Put up a large painting or print. And by large, something that really fills the space--I'm guessing by 3-4 x 5-6 feet. No dopey pictures of a girl holding a basket of flowers: Art. No family pictures. Put your family pictures in the hallway, not in the living room. Something that pops, something that fills the wall--whether it be one thing or a collection of things.
Say you want to go monochrome- a Motherwell B&W print or if that is too much, a huge blow up of a black and white photo. Look through Restoration Hardware for inspiration. But a statement.
http://www.restorationhardware.com/catalog/category/collections.jsp?categoryId=cat1701067
If you want to go green, or another color, think about a Rothko print.
http://www.markrothko.com/art.shtml
If you have the time and energy, you can buy a canvas and some paint and replicate your own Rothko. Study one or two you like and you can get really close.
Or a tall sculpture or a tall healthy plant (I like these the least.)
After you've filled the back wall, get one of those low wattage "over the painting" lights or a can up-light or a spot to focus on the wall. That will give you some extra light without overwhelming.
For your window coverings, I don't "get" the dark wine sheers. Depending on your view, keep the sheers light-ivory or grey. And is one of them plaid? I'd get rid of that. Your room does not want plaid. If you have the $$, you can have window coverings that change with your color scheme, but that probably is not necessary. Lots of good suggestions already. It depends on your budget. I could live with the light colored sheers.
Now you have the basics. For accessories, you appear to own a lot of little things, but little things will not work in that room with the big sofa and the big table. You either have to group them to make them feel bigger than the parts or get some larger items.
I see a plant on the floor, a couple of vases on a tray next to the tv. Try putting them on the coffee table. Aim to add your color scheme onto coffee table: A silver tray with green apples or filled with hundreds of sea shells (buy bulk by the pound for low $) or satin covered christmas tree balls. Scout thrift shops. I got a massive turkey platter in perfect shape for $3.75 at my Goodwill. They have all kinds of interesting doo dads that you can re-purpose if you keep you mind open.
Hide the remote(s) in something -- a box or a basket that "goes" with the color scheme.
Is that a plastic child's chair? It does not belong in the living room. Sorry. Go to a 2nd hand shop and find one of those child chairs in wood. Paint it. Depending on the color scheme you want, you can change the cushion to match.
Get something on your credenza. A fossil sculpture, for example.
http://www.arteriorshome.com/shop/accessory/sculpt/product/3236?fossil-sculpture
Again, something with panache.
Get rid of the toys in the living room.
I cannot tell what your rug is. It does not do much as best as I can tell, but I would not spend a great deal on a rug if you've got kids.
Do these things and then stand back and look again. Move stuff around. Remember, the mind likes groups of threes. Edit.
You've got a good space and a nice start. You are closer than you think.

I just read the bit about your kids.
For the back wall, you might consider something they identify with: artsy B&W photo of an airplane detail blown up or something they can learn from (map in your color scheme)
RE: 60-30-10 color scheme: You don't need 3 separate colors. You can go monochrome -- which is elegant and easier to care for with kids. As I mentioned above, you can add color inexpensively when you need a change.
You wrote: "The flowers on the table would be wonderful. The challenge here is to make the room child friendly. I have 2 little boys, they would hurt the flower every day.
I was thinking to put on round high edges chartreuse tray on the table, for the little snacks or water that we serve in the living room."

Good idea. Do they use that table for homework? How about gray tray with little baskets filled with "your color scheme" school supplies. If monochrome: white pencils, black calculators, gray sticky notes, clear rulers. If green: green pencils, green calculators, green sticky notes, green rulers, etc. Good practice for them to clean up at the end of the day.
When company is expected, you can stash the school implements in baskets in the credenza under the TV and change to flowers and candles.
Another idea: Do they have any collections of small toys they don't play with anymore? Old miniature car collections? Paint them in your color scheme (after they give you the ok) and fill the platter with them.
Use Pottery Barn and Restoration Hardware for inspiration; use thrift shops, ebay, etc for actualization.

Thanks all for your good ideas! The panorama photos that I've posted to this discussion are a little distortionated, they don't reflect well the proportions of the objects in the room and the colors, but I've understood the point about the scale, good point! Monochrome is beautiful, sophisticated, but it seems difficult to make. And i like colors, i have kids in the house, i think colors are good for us :) I have a 5x7 feet rug, i think it's size it's perfect for the couch, and it's a fuchsia shaggy rug, but it is not highlighted in the pictures. All windows have grey sheers, and purple/fuchsia curtains. Removing them is not an option, because i just painted those walls, just bought the curtains (maybe after a while, when i'm borred of them or find something much nicer). The curtains usually stay like in this picture bellow, but at night we use them for privacy or in the morning for blocking the shiny sun.
Meanwhile I removed some of the toys in the living room. I've already tried to make a kids playground, but they still bring the toys and play around us, they look for our company, which i guess it's normal, and i try to enjoy it while it still lasts (my boys are 5 and 3 years old).
About the wall with the tv on, it was done to delimit better the living room. Before we had an open area, and no ceiling to upstairs. It doesn't looked good, at winter all the heat was rising upstairs, and it was very dangerous to have that open area upstairs with so little kids. So we've closed that area and I've also won an extra big dressing/storage room above the living room (I always said that the most important things to a home are the dressings and storage places, so that the house won't have such much clutter).
I agree with you, guys, about the granny table, we planning to modify it, it's wood and we can do that. Will cut down the legs a little, and we will paint it darker. I've also found this table but not sure if it's size it's ok for the couch and room. http://images2.okr.ro/serve/auctions.v7/2013/nov/27/7b2b7e46238849e18d44a9f5bbfca9a2-2589911-1000_1000.jpg
I want to make that wall with the tv on the focal point, in the future I'm thinking to put some modern furniture on that wall. Thanks anyway for the suggestions with the cool purple chest, I think it's interesting, but it would compete with the tv wall. But I like the idea of that cool chest, I would use it in the entry hall, which I also planning to redecorate.
Thanks for the links and the hints, I've noted all and I'm planning to improve the decor with some nice artworks on the walls and on the furniture. I will keep you up to date with pictures, I've noticed that in other disscusions on Houzz and I think it's great.

The pictures that i've just attached are old, i've already modified the curtains to be longer, on ground.

I like the plum/grey colors. As I mentioned above, it's easy to add and change colors throughout the year.
If you can re-jigger the coffee table, that would be great. But the most important bit at this point in your life is to ensure you are focusing on the fact that you have kids. You want a room that encourages their inclusion and participation. Find solutions to minimize their natural clutter production. Keep you eyes open for simple additions to enhance the space, keeping in mind the scale you are working with. Are you looking for a new ceiling fixture? That could be a statement piece and better, the kids can't get to it. Good luck.

Love the purple. But go lighter purple like lavender or change the ratio. The reason why the room is not popping is because you have gone for 30 purple and 10 chartreuse. Maintain the ratio with lavender or swap the ratio.

Here' are alternative pillows:

Alternatives for the coffee table.

It's a beautiful room! Looks better without the curtains tied back. If you would like to add color do this with larger pillow(s). Enjoy your space!!!!

I You are trying to create soft balance try a textured beige fabric on pillow! :) Again don't over think it. Enjoy it!