Which evil, malicious, despicable characters light up the screen?

Clarence Boddicker (Kurtwood Smith) from Robocop

He’s also a good bad guy.

Michael Wincott in pretty much everything he’s ever been cast in. (See, e.g., The Crow and Strange Days). I borrowed his voice for one of my own more villianous PCs in a CP2020 game, and was pretty decent at it.

Paul Newman in The Hudsucker Proxy. Sure, sure.

Patric Zimmerman as Revolver Ocelot in every Metal Gear Solid game other than MGS3.