My all-time faves are the first two mini-series. As far as stand-alone episodes, my favorite is Haul Down the Heavens, and I also like Cobra Stops the World and Excalibur. Basically any episode with Duke in full-on Cobra kickin' action gets high marks in my book. I also love eps where Duke and Flint work together, which are rare since mostly they weren't in episodes together as they both usually filled the "alpha male" role.