Album Debate: Six Degrees or Black Clouds

My sister told me awhile back that she would buy me an album.  I could not give her a definitive answer as to what album I wanted.  Now, I am seriously considering taking her up on her offer.  I want to get a Dream Theater Album, but, do I get Six Degrees of Inner Turbulence? Or, should I get Black Clouds and Silver Linings?  Listening to Black Clouds right now, very good opener (A Nightmare to Remember).

Edit: FYI, I don't do April Fool's