As you can see the left image is the default ACR 4.4 rendering (I only rotated it 1.5 degrees or so to level the horizon and upped the blacks). This image was taken right after sunset in Canyonlands National Park using my super backpacking friendly D50. On the right the same image, but with the camera landscape profile applied and two grad NDs. I also changed the white balance to cloudy. As you can see. Left - quite boring. Right - very nice saturated colors. The grad NDs can be applied by clicking on the little icon that looks like an actual grad ND filter. Without the grad ND filters, the image looks like this now:
First I applied a quick transition +0.8 exposure grad ND as in the image below.
Then I applied a broader -1.0 grad ND to darken the sky:
This trick allows one to create quite complex gradations. I added a tiny tweak of the curve and added a little clarity and vibrance and saturation.
Here is the final result (large in the link):