btw, i have four 12' in my apartment (ibook dual usb, ibook G3 800 mhz, powerbook 1,3 ghz and an iBook 1,2 ghz.) as you can see these range from 2001 (dual USB) to 2005 (ibook G4 1.2 ghz). putting the oldest ibook next to the latest i can't see any difference in screen brightness.
therefore...