Yes, Bart Kepple was the best.Especially because of the trick how he fooled Columbo when they were driving to the cinema where Kepple killed his assistant.Columbo didn't tell Kepple where the murder happened and Kepple was smart enough and he asked Columbo about it.We can see a disappointment on Columbo's face because he thought that Kepple will catch himself into a trap.
I liked Culp's performance in "The Most Crucial Game" best. He plays the very aggressive murderer who simply does not believe that Columbo can keep up with him. Unusual character twist. He covers his fear of being arrested by his attitude.