If you want to paint everything the same color, then you will need to find a neutral that works with all of the finishes, including the kitchen countertop, flooring, cabinets and the carpet (which looks very neutral, but sometimes those are the hardest to "match") So, I would actually look at some paint samples first, to get an idea of the direction in which you want to go (taupe, gray, greige, etc.) Then go and look at furniture. You will want upholstery which blends with the wall color but doesn't try to match it. If it's in the same family, go lighter or darker. Consider going with a solid color on your couch, and then adding occasional chairs, pillows and other accessories in some nice prints and additional accent colors. The OTHER way to approach this would be to find some piece of furniture or accessory which inspires your palette, and work backwards from that. The key, though is going to be the wall color, if you are pulling it throughout the house. You also will want it dark enough to blend in with the wood trim; otherwise the wood trim stands out too much and makes the room look choppy. Also, wood trim looks much richer against a darker tone.

At the windows, I would suggest some draperies to soften the look (lose the valances - very dated looking).

I definitely agree on losing the valances. These pictures were the ones used for selling. I also like the idea of going darker with the paint but at the same time I want the house to still seem bright and welcoming. For instance in the kitchen....it looks so dark with the black appliances, dark granite counter tops and dark cabinets. Do you think something like this would be possible for living room? The paint color at least?

Yes, I think that would look very nice! You know, sometimes you just have to go with the room. Using a light color to keep a room "light" oftentimes just ends up making it look washed out, uninteresting and sometimes cheap. I think a richer color, like you show, will warm up the wood and make it an asset. You have light carpeting (if you are keeping it) so that helps keep the room lighter, and you can choose furniture which gives you the same appearance (a la the photo you posted!) The vaulted ceilings help immensely with this, too. In the kitchen, because it does appear kind of dark, you might want to lighten the color a bit (maybe a couple of shades lighter). Also, add lighting: you can install lighting on top of your cabinets (as well as underneath) which will do wonders in brightening the room - much more so than recessed cans which really don't give off a lot of light. Adding a light colored tile backsplash with a bit of darker accent in it (to pull the finishes together) will also go a long way to brightening it up.

Tan would be a nice color for the walls in both rooms. Your kitchen has lots of rich browns and black color in the room. Tan would work well with the wood trim, counters, cabinets and floor. If you'd like, you could get the furniture before painting, that would be up to you. With Tan, just about any color furniture would go nicely with it.
A nice rug and a change from valances to panels would update the living space also.