The 'Due South' episode was a season three episode entitled 'The Ladies Man'. It was okay. Stan didn't annoy, however Fraser was smug and Dewey continued to change personality from episode to episode.
The 'Earth: Final Conflict' episode entitled 'Moonscape' was from either season 2 or 3. After season 1, the show became a collection of dreck you couldn't tell apart. Liam was smug and existed only to annoy, but was outdone in annoying by Maya, who has to be the worst character ever. This episode was full of plot threads that the show dropped: characters from parallel dimensions (Maya), the fact Lili discovered she had a half-sister named Isabel, Sandoval's obsession with Maya and the fact killed off season 1 lead Boone was recreated (and recast) as a character, named of all things Lazarus. This was an ugh of an episode and I haven't even bothered to describe Augur's badly acted A-plot.
The 'Nash Bridges' episode was 'Out of Chicago' where Melinda Clarke of 'The O.C' guest starred as a bad cop from Chicago who was out foxed by Nash and his freaky cosmetic surgery gone wrong face. This wasn't bad, just mediocre.
Finally there was the 'Xena: Warrior Princess' episode, possibly from season 4. It guest starred the chick from 'Roswell' in a bad wig and ripped off the plot of 'Footloose'. Bruce Campbell wore an idiotic hat and there was bad dancing, worse acting and general dullness. Xena got to utter the line: "It ensures that anyone who gets in your space loses an arm, a leg or a vital body part" while teaching a dance class disguised as a combat training class.