The scariest characters in the LOTR?

Not the Witch King. Dont get me wrong, I like the guy, but he seemed to make too many mistakes to be the scariest servant of evil.

Probably Durin's Bane, considering Gandalf's and Legolas' response upon seeing him.

Without his ring, would Sauron be as powerful as Durin's Bane? My initial guess is no, though I have little from the literature to back that claim up. And then, since Tolkein doesn't personify Sauron very well in the trilogy, it is tough to guess much of his power (and scary factor) very well. Though being an enigma might help his case.