just found this info so i guess it is normal...
"Canon implemented a new viewfinder on the EOS 5D, covering 96% of the recorded frame in a 0.71x magnified perspective. The viewfinder has a 20mm eyepoint with a -3 to +1 dioptric adjustment. Some users may object to the 96% coverage, seeking the full 100% view provided by the 1Ds Mark II; however, those who have made a career shooting with 35mm bodies have likely become accustomed to the crop and have learned to work with it. Those who remain disenchanted with the 5D’s viewfinder coverage might at least take solace in the manner in which the view is altered. Unlike the 20D, which primarily took its 5% liberties from the top and left segments of the frame, the discrepancy in the 5D’s recorded frame is much more evenly dispersed. Files recorded with the EOS 5D will contain about an eighth of an inch more of the scene all around the frame, resulting in a far more accurate representation of the composition."
although having put up with it for the last few months its now getting to be a real pain...takes the art and technique out of strict viewfinder composition in interiors.