Almost all Dragonwyck's editions have the mysterious Gothic manor in their covers, which couldn't be more appealing to me. You suspect only by looking at them that something strange will happen in that house. The most recent edition in English language (number 7) is beautiful but somehow out of place. The French edition from the 60's (cover 8) is in perfect harmony with the other covers.
My favorites are the two first ones featuring the couple, Miranda Wells and Nicolas Van Ryn with Dragonwyck in the background. Actually, the second cover seems to be the movie tie-in with the actors Gene Tierney and Vincent Price.
Do you have a favorite?