If you're thinking urban fantasyish, I'm right with you in finding the whole "huge secret history full of stuff that nobody in the mundane world knows about" hard to swallow, and would favour either of the latter two.
For what it's worth, one of my favourite recent examples of a sort-of broken masquerade is the Felix Castor series, where there have always been ghosts but they have been very rare and about ten years before the story starts they suddenly became much more common, along with other supernatural stuff, in ways that are generally known and having impact on mainstream society; figuring out what's going on and dealing with the consequences are a large part of what makes those books so good. As for sort of AH, I very much like David Wellington's Thirteen Bullets and sequels, which does a rather nice riff on the "if I didn't know better I'd think this looked like a vampire kill" thing, in which it turns out that the reason the cops are sure a vampire kill is impossible is because vampires have been extinct since the 1980s.
