How about doing the walls in a warm tropical blue, a lighter shade of what you have in your area rugs? Another option would be to use a lighter shade of the green in the rugs and pillows. Bring paint chips into the space to see how the colors look in both natural and artificial light, AND remember that the color will come up darker on the walls than it looks on the chip.

Pale blue would work, but please choose a shade that is a bit greyish. Otherwise the room will look like a baby-boy nursery.

Alternatively, I think that wallpapering the wall behind the sofa would be really cool to make it an accent wall (the rest of the room can be painted). The wallpaper can be white with some blue and some other accent color you choose to have in your new rug. This can help bring some dynamic into the large room. A few examples:

http://www.fashioninteriors.co.uk/sanderson-wallpaper-50s-miro-collection-dfif210234-dfif210234/p120915.html

http://www.vervedc.com/Lists/WebLayoutPage.asp?Row=110804&Layout=&Ref=7614

http://www.remodelista.com/products/eijffinger-degrado-rosado-330283-wallpaper-yellow

I like Vanguard's suggestion of 'old gold' (disregarding the big ottoman on the miniature rug) -- or slightly lighter, what I think of as a beach sand colour. I think it would look even better with your lighter blue upholstery, compared to the picture posted.

I was going to say go with a light grey on the bluer side of the scale -- then the walls won't constrain your decoration choices in terms of furniture and accessories...