I can't say if he's my absolute favorite, but I always thought that Kurtwood Smith was very underrated in Robocop. He make Clarence Boddicker so much more than the cheesy asshole who you know will get his at the end. His deadpan delivery of lines, the blatant disregard he holds for his own men, and the overall menacing quality of his appearance (Verhoeven thought he resembled Himmler) all contribute to a character who you love to hate, hate to love, and personally, find myself enjoying each moment he's onscreen.
As for female, one of my favorites is Mrs. Iselin, excellently played by the wonderful Angela Lansbury. Her icy demeanor, ultimate maliciousness in using her son to achieve her means, and her intelligence and the vileness of her plan all play a part in creating one of the most diabolical villains ever.