BEST Licensed Minifigure, to my eyes, is Indiana Jones. The new fedora, the satchel, the right amount of printing on the torso and the holster on the legs. LEGO did a really good job at transposing the old charm, and the rugged and beaten nature of Indy into a minifigure. That Indy came in every set didn't diminish the well-executed design. Really, come to think LEGO Indiana Jones gave us a lot of really good licensed minifigures, including Henry Jones Snr and Mola Ram.
That being said, the title of Best Licensed Minifigure for me is also a close tie with Jango Fett. There's a simple, sleek simplicity to his design which I find appealing, in addition to the silver and blue colour scheme. It also helps that he's frustratingly rare!
WORST Licensed Minifigure is, beyond a doubt, every single Podracer character ever made. Aldar Beedo especially, going by the pictures posted on this thread. Bleeeegh.