There's a few places where we have blue & black text on a blue background:
Previous version: https://i.stack.imgur.com/EqJea.png
Update: the issue now is the over-large bottom border when the "awarded to" section is short.
Previous version: https://i.stack.imgur.com/pTeqC.png
Update: now looking much better; only current issue (imo) is the black "Return to Question" header on the dark blue background.
There may be others, but these are the ones I've run across.
I don't think that any of them are due to my custom CSS or GreaseMonkey scripts, but if they are, feel free to publicly point at me and laugh.
January 30, 2011: updated 1 & 3 with new screenshots and updated descriptions.