<p>ilikedrit - my 3rd letter pretty much said the same as your “flat” letter, and I got in to every school to which I applied save MIT. What you are missing is that the “flat” letter you listed is still better than a grad student letter. It is okay if you have not created a deep personal relationship with every professor in the department, but a letter from a grad student implies that you could not even get a professor to say “He got an A and participated in class.”</p>