From a quick play with the RC I noticed a couple of changes to the classic theme:
Progress bars now have blue backgrounds, not white.
When a grid row is selected it has a black dotted border, not blue.
I just wanted to check these were intentional as they jumped out at me right away. The change to grids is particularly striking. It seems to be something to do with focus styling trumping selection styling... Personally I don't like it, it really accentuates where the dotted borders don't line up at the cell boundaries.