My top favorite is and has always been the Postmark Lenormand by Melissa Hill.
I think I have about 100 lenormands, but other top favorites are:
Le Fanu's Destroyed
Shaheen's Tattered Nomad
Breath of the Night
Revolution
Dust Bunnies
Pictorial by AlyZen
Flonz
Antiquarian
Magisches
Malpertuis
Mysteries of the Old Castle
White Owl
I know it's kind of the "Rodney Dangerfield" of Lenomand decks among the purists here, but I get especially good readings with the Gilded Reverie. That said, there are a few more traditional (and not-so-traditional) decks I still want.