If a show has monsters, magic, or is by Shonda Rhimes I watch it. Right now The Vampire Diaries is my favorite hour of brain numbing activity, followed by True Blood. Being Human is getting up there, but I right now I would watch Grey's first.
While I am slightly embarrassed at how "main stream" my choices seem to be, I would like to point out that I watched all Joss Whedon shows religiously (except for Firefly, which I made up for in late night marathons), and that I could still watch Xena for days without a break. My bookshelves are overflowing with mystical and magical stories, with the Wheel of Time and the Kushiel series having top billing. I may seem like a lemming, but I like to think of all of these fair weather vampire fans as the same sort of people who rooted for the Saints only when they were winning.
Now I want to go read a book. Figures.