Evil wizard and evil priest are classics for good reason. With magic on their side, they can provide a wide variety of potential threats.
That said, I think both are improved a lot with modified Vancian casting (like Pathfinder's arcanist or 5e's casters). It lets you adapt the villain to the party's tactics while also simplifying tracking when you're actually controlling them in a fight.
When you can use a non-magical villain, though, I think it's almost more emotionally effective. In my experience, they feel more like real people than archetypes, just because they can't drink as heavily from the fantasy well.
In those cases, people love a good enemy paladin, but any of the martial classes can make a pretty convincing villain... if not always the most effective one.
Cheers!
Kinak