Hans, I've had the nik Color Effect Pro 2 "plug-ins" for some time. I agree they are a lot of fun. While you're at it, try experimenting with some partial filter use where you apply an effect to one part of an image and not another.
I like the drama in the skies you've created in the second image. The image seems a bit noisy though. Was this you intent?
Virginia
aka beaucamera