I have had quite a few people ask about my skin smoothing ways. Its really, really simple. I use Imaginomics Portraiture 2 and have figured out how to get it so it smooths the tones instead of all the texture. So if you use Portraiture, follow along and stop killing your textures!
For a quick look at the settings, they go in this order:
Also, make sure you check layer mask, and make sure it creates a new layer for each smoothing process!