Obama Is The Most Unknown Presidential Candidate. What is he hiding?

We are just about 10 days from the election day, and we are still waiting for him to release  these documents:

His birth certificate.  Read here, here, and here

His medical record. Read here , here 

His college transcripts.  Read here, here

His paperwork as State Senator & his years in New York.  Here

Finally an article on WSJ:  Obama's Lost Years.

So what is he hiding and why?  Shouldn't the media look into these missing information rather than trying to follow Palin's shopping list?