The official official place is http://bugreport.apple.com/. It's where developers can file bug reports/feature requests/enhancements, etc. You do need to sign up for a free developer account to be able to submit bugs, though you don't necessarily need to know how to develop apps for OS X.
When you submit a bug through the feedback form, it's possible that someone at Apple will manually create a corresponding bug in the bug reporter system, but there's no guarantee.
Bugs submitted through the bug reporter (often referred to by its code name
Radar) all have an official number and status (open or closed) that you can track.
Compared to the feedback form, the bug reporter can potentially offer more in the way of feedback from Apple about the bug's status: Open, Insufficient Information, Duplicate, 3rd Party to Resolve, Behaves Correctly, and Closed.