I actually voted for Kiln House because I think it's pretty and also interesting how it was before LB/SN yet reflects that California/mystic vibe they brought.
Obviously, Rumours iconic, but felt I had to be different
I also really like the SYW and Mirage covers. Tusk not so much, my favorite musically, but the cover looks like an old textbook lol - you know the kind with a crappy graphic and title? For the life of me I can't find an image on Google, but anyway lol just mho.