The really cheesy Sci-Fi actors were found on shows like "Battlestar Galactica" and "Lost In Space". Dreadful stuff. I vote Lorne Greene as the cheesiest actor of all time. I shudder to think that he is Canadian. And then there's Leslie Nielsen, but he doesn't pretend to be anything BUT cheesy.

Alongside those guys, Shatner is a veritable Olivier.