i've had my macbook for nearly a year now, and i've had quite severe discoloration and also constant screen flickering recently. the discoloration i could handle, i just got a macstyles skin to hide it (i don't have time to part with my computer and the service here in australia is atrocious), but i can't stand the screen flickering anymore.
I guess it serves me right for buying a first gen laptop. Otherwise, i wouldnt exchange this little white beast for anything! except maybe a Mac Pro with four apple displays...... ahhh.....