Paul - A circular polarizer really helps with the green trees/deep blue skies pictures. I've been using it more often (it rather lives on the FA 31) and getting more respect for it. It sometimes makes things worse, it's taking me a while to make peace with it, and use it effectively.
The patterns in the glass were really cool, I just wish I had gotten more good shots, I somewhat struggled with it - there were a number of unexpected challenges. I had expected it to be really easy - I mean, my thought was how difficult can it be (well, there's the background, the focus, the dof etc. - all problems that have to be solved). I'm finding photography is harder now than it was when I bought my first dSLR.