Originally Posted by BMWN54tech
Rule of thumb, start from the top. Did you roll the gasket accidentally? Check with a mirror. First gasket I would do is the oil filter housing. When it leaks it leaks onto the lip of the oil pan gasket and goes everywhere.
Yep, you beat me to it.
I guess the question is this: was the big puddle present before you did the valve cover job? If not, it's pretty damn likely the valve cover gasket came unseated. And like N54tech said, the oil filter housing is by FAR the most common oil leak on these engines.