Well, I guess I'd work from your rug for the living room -- maybe pick a tan shade from the corners there (or lighten it a bit) for the walls, to get the contrast you want with the white trim. You might want to see your rug in place before doing more. For example, that might bring enough color, such that a few throw pillows and some coordinating pieces in the bookcases (reds, navy, more rug colors that you like) would be enough. Or for really high drama, you could paint the rear wall of the bookcases red or black/navy (don't trust my monitor on what the darkest rug color is), or even a gold leaf-type paint that might coordinate with the walls a bit while bringing some Mediterranean glitz.

No ideas on diningroom. If that's your table, then you can do anything you want, since it matches the floor. If it's not, then I'd pick what your color scheme is going to be -- e.g., based on chairs? rug? large art you intend to hang? -- and figure out how to echo that in the walls. But honestly, the gray looks pretty sharp, so you might do everything else first, and paint only once you're sure the other elements are settled. Paint is easy...

I think the existing wall color is beautiful and sounds like it will work nicely with your gray sofas. Do you have pictures of your furniture? The existing color certainly serves as a very neutral backdrop for your colorful area rug and makes the white trim pop. I would move in with your furniture and see how you like it.

For shelves color beige or pumpkin from rug.