I used to think Tarkin was just obnoxious, interfering with the cool Darth Vader when I was a kid. And I imagined that when he approached Leia saying, "I grow tired of asking this..." I couldn't help but imagine some old man with bad breath breathing, "Hhhhhwhere is the Rebel base?" across her face and up her nostrils. But now as an adult, I find his character very fascinating, a very different villain from Vader, but quite threatening and interesting in his own regard.
I think Dooku had potential but was wasted.
And I have to admit, when I first came up with darth_ender, it was an homage to Darth Maul, though now I prefer to relate it to Darth Vader, still a very cool bad guy.