This first image is very, very similar to (though a bit smaller than) our friend's living room. They have hardwood floors, exposed beams, white walls, a large window on the far wall, etc. I think this sectional really works here.
I like how sectionals can be used to frame the focal point in the room - in this case, the fireplace and television.
I like how the velvet fabric really ups the "cozy factor" for this sectional.
Here, the sectional helps frame the conversation area.
This Pottery Barn picture is gaining a lot of steam on pinterest. Since I pinned it, it has been repinned 21 times. I added it because of its neutral color. However, the room is too beigy for my taste and in my opinion, needs more contrast.
Love love love this room! Though I just endorsed neutrals ... don't be afraid to go for the color (especially if you have kids). It will hide the dirt. I love this color palette: eggplant with the burnt orange.