This is one that's been puzzling me for a while.
I installed the ati-drivers recently, having managed without them for a while, and one colour in my terminal has completely changed:
You see the yellow colour for the line numbers in vim, rhs of the first screenie? Well it's now a gay (as in jovial ) pink in the second screenie.
Also, that particular colour changes again when I go from urxvt with Screen running inside it to just vanilla urxvt - it becomes a deep red.
In the words of the dyslexic anti-'Weights Fitness Training' protester, "WTF is going down!".
.oO Komodo Dave Oo.