I think V. Klitschko is probably the correct choice as of right now. For a non-HW fighter, I think the earlier poster's point about Kirkland and Angulo is solid. When Mandingo gets out of jail, I think he's probably right up there with Vitali.
While most fighters probably think they will lose to guys like Pacquiao, Mayweather, and Mosley, none of them strikes me as all that intimidating. Mayweather comes off as a clown, while the other two smile like alligators all the time. Being intimidating is not necessarily about being the best. You need to be good enough that people will have reason to acknowledge the appearance, but it's not sufficient. Guys like Vitali are not only dominant fighters, but they have death stares that would make a lot of people go cold before getting KTFO.