Okay, first... vampires don't "sparkle". Period.
Second, never before in the history of television has a vampire caused such a fanatical uprising as Barnabas Collins! No one will ever be able to do that again. Teenage girls would rush home to swoon over a middle-aged actor. Why? Two words... Jonathan Frid. I simply don't think any other actor could have pulled that off like Frid did.
So, let them try to put Twilight on television. It will be about as popular as Buffy the Vampire Slayer, Charmed, or any of those other shows that I never watched. Which is totally fine, I mean, Personally I want Twilight to hit the airwaves (okay, after June 12, we won't have "airwaves") and maybe more people will want to discover or re-discover Dark Shadows!
I can not wait to see Johnny Depp as Barnabas! He's an amazing actor, and I don't see him having a hard time with this at all.