<p>I think a much more useful question would ask which departments aren’t excellent. The NRC rankings may give you some idea:</p>
<p>Comparative Literature #1
English #1
French #1
History #1
Political Science #3
Psychology #3
Art History #5
Classics #5
German #5
Music Theory #5
Molecular Biology #6
Economics #6
Math #7
Anthropology #8
Chemistry #12
Physics #13
Computer Science #14
Astronomy #15
Ecology/Evolutionary Biology #17
Sociology #19
Linguistics #30
Electrical Engineering #30
Chemical Engineering #32
Philosophy #58 (ouch)</p>
<p>Yale also has superb programs in interdisciplinary departments like American Studies, East Asian Studies, Medieval/Renaissance Studies, and Near Eastern Languages & Civilizations.</p>
<p>The six most popular majors are history, economics, English, political science, biology, and psychology (roughly in order).</p>