This is a tough one for me, since I have, at various times, enjoyed each of them, but, also, each of these tropes became oversaturated at some point or another! If I had to choose, right now, I would choose werewolf by elimination, because I overdosed on vampires and I never really liked zombies, although there a couple of zombie books I liked a lot.
I was never a fan of Twilight. My YA vampire romance catnip were the Morganville Vampires and Vampire Academy - those were the ones that my daughter read, and that I read along with her. Oh, and Buffy the Vampire Slayer, on television, of course.
Now that I've put some distance between myself and far too much sexy vampire fiction, there are a few series that I'm interested in again, though! The Chelsea Quinn Yarbro St. Germaine series has been recommended by several of my friends here - including Linda Hilton, whose bookish taste is impeccable. The first book, Hotel Transylvania, is on my list of possibles for this years game of Halloween Bingo, unless someone who knows the series recommends a different starting point! I also have a copy of Anno Dracula on my kindle that has been there for years, and that looks like something I would love!
Moving on to zombies, they just didn't appeal to me. Sexy vampires are silly, but there is nothing sexy about a zombie. On the other hand, World War Z is worth reading, and The Girl With All the Gifts is excellent, with a great ending. Too many authors blow the ending, and Carey nailed it.
There are exactly zero is one possible zombie books that I am sufficiently interested in to plan to read for Halloween bingo at this point, although I'll keep my eyes on the posts for something that might interest me. No, wait, there's Feed by Mira Grant. I might read that one!
So, that brings me to werewolves, which brings me to urban fantasy. Urban fantasy is replete with shifters of all sorts, and I pretty much lump werewolves with shifters. My favorite shifter has to be Mercy Thompson, who is actually a skin walker (shifts into coyote form), not a werewolf. I read the hell out of Mercy Thompson and keep meaning to do a reread! And I can't mention shifters without pointing to Kate Daniels, which may be the actual best UF series ever written.