Rosetta (S2 E17)

Christopher flippin’ Reeve! John Williams’ score! The first mention of Kal-El and Krypton! Sure, this one was a bit of a sudden infodump but it’s the single most exciting episode yet.
Exodus (S2 E23)

Clark fights against fate when his father (Terence ‘General Zod’ Stamp!) orders him to fulfill his destiny. A thrilling, and surprisingly dark, finale with an even better multi-cliffhanger than season one.
Exile (S3 E1)

Clark has gone bad under the influence of Red Kryptonite while Lex is stranded on a desert island, all Arrow-like. A very different episode that makes for amazing drama.
Shattered (S3 E8)

Lex uncovers a conspiracy to kill him constructed by Lionel and Morgan Edge – or is he just losing his mind? Terrifically tense with a superb performance from Michael Rosenbaum.
Asylum (S3 E9)
Multiple returning villains, a DC comics setting, lots of poor old Lex and the exploration of the depths of Lionel’s villainy makes for another superlative episode. A treat for Smallville fans.

