I just upgraded to 2.9 for one of about 50 WordPress sites I have built and still don't see this feature... have been asking for it since about 2.6.
Any chance of seeing the possibility of uploading files and having their URL be easily placed into Custom Fields without a lot of copy/paste nonsense in a future version? Is there a workaround now I could be using?
By way of explanation, I utilize Custom Fields for a lot of file linking, custom image placement, etc. and this is really the only thing that keeps the sites I build from being super easy for clients to update.
Otherwise, LOVE WordPress... keep up the good work.