They have so many great songs but my favorites are:Master of puppets,Fade to black,One,Blackened,Wherever I may roam,Enter sandman,Sad but true and Seek and destroy
Ehn. They have lots of good ones, and even though I don't really like Metallica all that much, I appreciate their writing and talents. My personal favorites: Master of Puppets, Welcome Home (Sanitarium), One, and The Ecstasy of Gold.