Let me just start off by saying that I don't give a crap if your vampires sparkle in the sunlight (though that does seem kind of goofy, honestly) or die screaming. I don't care if your were-beast is a shaman in animal skins or a really hot dude or Lon Chaney, Jr. While I am open to all possibilities, as far as I know these creatures are mythological and have never actually walked the Earth. And mythology changes constantly (example: every ancient god is patron of three or four different things), so do what you like.
I do have two problems with your glittering vampires and hot were-creatures: 1.) sheer overexposure and 2.) they're fucking indestructible, unbeatable, and kind of ridiculous.
Now, much vampire lore was actually created by Bram Stoker. But if your vampire can walk in the sunlight, cross running water, pick up a crucifix and come into your house without your consent, then how the Hell are they ever going to be be injured/die? Even if your bloodsucker is a good guy, there's no tension if I don't believe they could ever lose whatever fight they're fighting. Especially if your vampire can fly faster than the world turns on its axis so it can always stay on the night side of the Earth (Anne Rice, Queen of the Damned).
And if your werewolf/panther/whatever can change on command and is not at the mercy of the moon/wolfsbane blooming/silver bullets- or cane heads-, then where is the tension? Where is the fear and worry for your character? Where is the moral torment?
Where is the interest for me, the reader?
All creatures have limits. I can't run for exercise (I always end up puking). My cat can't jump to the top of the china cabinet. My husband can't see without corrective lenses- like, really can't see, I asked him once what he tell about me from two feet away and he said, “I can tell you're a person.”. Everyone has some flaw, psychological or physical- usually both- that prevents them from being perfect. Everyone has a limit that comes from the inside. Even if you're undead, living dead, a shapeshifter, or Superman. Without limits, we are not interesting. And neither are your vampires and werewolves.
And why is is always vampires and werewolves (and zombies, to a lesser extent in fiction but probably an even great extent in movies)? Where are the wendigos, krasue, kappas, Yeti, wyverns and duende? Every culture in the world has a rich history of the supernatural. USE IT (I've hit wendigo, krasue and kappas; I still have a way to go). Whether you're writing horror, urban fantasy, romance, whatever, spread your horizons a little. There's a lot out there if you're willing to look past the vamps and were-things, and most of it is damn cool.