This one is pretty tough for me, since I love a well written story about any of them.
I thought I'd mention a few of my favorites that aren't as popular as others in the genre.
A hot, dark haired, green-eyed werewolf spy during WWII. Nuff said.
A werewolf that only kills...killers.
(Like a Dexter of werewolves.)
Oh, and the werewolf cooks!
One of the major benefits of living forever-think of all the books you could read!
This novel involves vampires seeking knowledge. Knowledge about everything.
Literary and unique, I loved this book.
This series is about a vampire, but they're not horror, they're historical fiction.
Extremely well researched and sometimes horrifying, (not because of vampire violence, but because of the customs in various countries over time, especially those regarding the treatment of women.) This may be one of the longest running series' ever.
This series is cool because it features a zombie who is actually aware of what he is doing, due to a medical experiment gone wrong. Imagine yourself being a zombie and doing zombie-like things while being fully aware of it, and unable to stop it from happening.
I love me a good creature feature and Hunter Shea writes some of the best ones out there. Who doesn't like to read about giant mutant lizards running amok? ;)
In short, I guess my answer is all of the above, plus some!