I feel like those are pretty neutral colors all around, so you can do almost anything as accents. Teal might be nice.

A powder or smokey blue, with some design or image on them would be a nice compliment to the cozy light in there. A big piece of art on that wall couldn't hurt either. :)

I would pick up the gold color from the lamp and rug. Or maybe pink, like that flower you have on top of the bookcase. In any case, what a gorgeous room!

Bright blue and some terra cotta would work well with the brick and against the grey. Look for patterns you love to break up all that square geometry.

Use any colors that make you happy. You

Is there a color you want/need to repeat from the other side of the room we can't see? I change my pillows seasonally - greens for spring/summer and reds/burgundy for fall/winter. Both colors are in the cream-based area rug in the living room...I agree with the above advice from Murphy, too.

I am actually going through this same issue only my couch is a different IKEA make. I'm really considering a mustard yellow or coral. Something springy, bold and bright but not obnoxious.

I would look for two different types of patterns, one large scale and one small scale, that share some of the same colors, and then a few solid pillows that pick up some of the colors in the pattens.

As for the colors themselves, you could put almost anything - I like the pink from the flowers or the orange from spines of the books.

Thank you all for the comments! So many ideas now. To Coni: no, there is no other dominant color in the rest of the room. Except for the floors, which are a warm brown. And the brick, of course. I thought of buying some Moroccan poufs to brighten up the room though. To Murphy: I agree with the art piece comment. I am on the lookout for a nice one at a reasonable price!

That rug is gorgeous!

I really love this pillow:
http://www.etsy.com/listing/74486743/handmade-pendleton-wool-pillow-cover

If I could fit it somewhere in my house I would. It would look really beautiful in your home, too!

I am insanely jealous of this room!

To jessicamc: I got the rug from Maryam at http://moroccanmaryam.typepad.com/my_marrakesh/ if you are ever interested in Beni Ourain rugs. It came all the way from Morocco in less than 2 weeks. It felt like a little adventure.

Paola, how comfy is the couch? (My twin and I are thinking about buying one in the light grey, but there isn't an ikea with in 3 states of us so we can't sit on it in person.)

Xtina, the couch is very comfy. The only thing is, the cover in the teno grey color is a bit scratchy at the beginning. So, you might want to get a cotton cover instead.

This person has the same sofa as you see what she has done with pillows.

http://www.justalittlebit.net/2011/02/19/updates-living-room/

You could go seasonal with the same hue, just change the saturation, tone or shade depending on the season.

I think reds or oranges would go well with your room. Spring and summer, corals, sherberts, Fall and winter, raspberries, fuchsias, garnets.

And you could break up the warmth if it's overwhelming with cool hues. Teals, turquoises, sages.

Overall, I just wouldn't do a straightforward primary color.

And of course, you can always do hues that make you the most happy!

Great space, by the way!

I suggest white or cream to lighten up the space and keep it neutral, and then putting a big colorful piece of artwork above. I'm so jealous of your brick wall and huge window!

I instantly see burnt orange and reds, maybe mustard or browns in a big bold graphic prints.
See the cushions on the floor in the first picture, they would look great.
http://www.apartmenttherapy.com/la/bringing-the-fun-back-into-the-home-hanging-furniture-145813

Go here to play with the colors. I think larger pillows in a wool would feel just right.
http://www.jonathanadler.com/designyourown/

It's a really nice room, and I agree with people who say to pick a color that makes you happy. Do you have any item in a favorite color, even a t-shirt or towel? You could wrap it around one of the pillows you already have and SQUINT at it to see what it would look like in the room as a real pillow.

go to crate and barrel and choose something from their solid pillow lines, especially the hayward which is silk weave. the texture and sheen will contrast with your sofa and rug.

blue and white graphic designs.

Yellow pillows would look fabulous!

I would look towards the colors of the flower, throw in some gold, and the colors coming from the window- white/powder blue. And I agree with Anita83 with the seasonal changing. And don't forget to play with the textures of the pillow cases too!
Have fun! <3

I would go for some really bold bright yellows, also some prints in there (like giant houndstooth in inky blue and white)

If you want to be somewhere between completely neutral and super-bright hues, try a soft metallic - copper and brass are really in right now and you can usually find interesting shapes and sizes in throw pillows!

My initial thought was to play off the colors in the bricks, but since that idea was well-spoken for, I kept thinking.

What's outside your window? If there are colorful buildings, or trees, or a body of water, you could maybe play off those and bring your surroundings in.

Or, instead of focusing on colors, focus on patterns and find things with the same criss-crossed pattern as your rug, and get them in many colors.

Just trying to be outside the box.

I agree with CaitlinHuman, bold and bright, with some prints mixed in. Anthropologie has a lot of great prints, and if you scour the sale section, they can be reasonable.