My favorite episode changes from day to day, but right now I'd say it's "Tempus Fugitive". I've always been a sucker for time-travel stories, and this is the first time we meet the delightfully snarky Tempus. (You know he was too great of a villain to have only one episode.
)
Plus, Lois finds out the Big Secret, or, rather, she's *told* the Big Secret. The "galactically stupid" line is just awesome. And Clark's reply: "You haven't talked to me since 1866!" Comedy gold.
But hey, in the end, Lois saves Clark's life and they are reconciled. You know they're going to start a new relationship... of course, then the writers pull the old "due to time travel, it never really happened" trick. So we can go back to banter and flirting.
(But Tempus comes back later - YAY, for me, as I am a fan of snark.
