I have to say that I like the entire led zep discography but I'll play along with you regarding a fav.
1. Led Zeppelin the cover of willie dixon's "I can't quit you Baby"
2. Led ZepII "Heartbreaker/living loving Maid" played back to back.
3. Led ZepIII "Tangerine"
4. Led ZepIV the final cut "When the Levee Breaks" tough call because the album is excellent in it's entirity.
5. Houses of the Holy "D'yer Maker" and the question was never answered but one can only assume he did
6. Physical Graffity a toss up between "Custard Pie" and "Black Country Woman"
7. Presence "Achilles Last Stand"
8. In Through the Out door "In the Evening"
9. Coda The 1993 CD release track 12 "Hey, Hey What Can I Do"
I didn't purchase the original vinyl release of Coda but did the CD for the final track. In time I came to appreciate this last album (such as it is).