I can only supply my observations:
The Konica Minolta 7D is much better suited for low light work, less noise plus the anti-shake feature. The 7D also has a built in flash.
The Olympus E-1 is built like a tank, pro quality body with lots of dust and moisture seals. The hypersonic dust removal is a plus as well. However like most pro models it will require an external flash.
For most photography you will not notice a difference between 5 and 6 megapixels, it amounts to only a 20% increase in area at the same output resolution. I have seen excellent 11"X 14" prints from a 5MP camera.