So today I did a test: I put a circular polarizer on my EOS 1D3 with the 24-105 lens and shot at a few polarizer settings (equal exposure). I took the "strongest" polarization effect and the "weakest" and went to play!

And then, for the comparison is a Before shot using the strongest polarizer setting (you rotate a filter "cuff" until the view darkens to the max amount).

The After shot shows the effect when you add some of the same Raw processing to this shot...

My thoughts? I was very pleased with the outcome of the Raw processing on the first one! Although polarizers do more than just affect blue skies, I really love how the Raw process of pulling back on the Blue Luminance channel pays off!