These rankings are of course intensely personal, and forcing them all into a ranked countdown isn't particularly helpful. It should also be pointed out that evaluating episodes at any given point in the LOST saga could be misleading. The real importance of certain things cannot be grasped until the whole story can be seen. As an example, "Flashes Before Your Eyes" became a lot more importance once time travel went from being a one-time anomaly to a consistent theme on the show, and as Eloise Hawking emerged as a key character. From the current, post-season 5 perspective, this is how I see it. All centric-episodes are conventional flashbacks unless otherwise noted:
22. Whatever the Case May Be (1x12, Kate)
Episode highlight: Kate as a bank robber is kind of hot.
Episode lowlight: Love triangle...blech.
21. Outlaws (1x16, Sawyer)
Episode highlight: Locke has a chat over coffee with Kate and Sawyer.
Episode lowlight: Love triangle...blech.
20. Born to Run (1x22, Kate)
Episode highlight: Walt warns Locke not to open the hatch.
Episode lowlight: Love triangle...blech.
Honestly, I like Kate. She's my third-favorite character among the original Lostaways (behind Jack and Sun). But her centric-episodes generally fall flat as the flashbacks involve endless variations on the fugitive theme, and the "real-time" portions often center on her love life. It is very much possible to love a character and hate her flashbacks.
19. The Moth (1x7, Charlie)
Episode highlight: Sayid gets knocked out as he attempts to triangulate the French transmission
Episode lowlight: The second cave-in
18. Hearts and Minds (1x13, Boone)
Episode highlight: The introduction of the idea of electromagnetic anomalies via Locke's compass
Episode lowlight: The hallucination-fakeout death of Shannon
17. Confidence Man (1x8, Sawyer)
Episode highlight: The reveal of Sawyer's backstory
Episode lowlight: Love triangle...blech
16. Tabula Rasa (1x3, Kate)
Episode highlight: The conversation between the party that heard Rousseau's transmission
15. ...In Translation (1x17, Jin)
Episode highlight: Locke confronts Walt about burning the raft
#2: Sun screams "Stop" in English...we knew, as did Kate and Michael, but it's still quite a bombshell
14. Special (1x14, Michael)
Episode highlight: Walt displays his abilities as the bird crashes into the window
#2: Claire stumbles out of the jungle
Episode lowlight: The CGI polar bear
13. Homecoming (1x15, Charlie)
Episode highlight: Claire and Jack have a chat that resonates more when we realize they are siblings
#2: Ethan confronts Charlie, again, creepily
12. Do No Harm (1x20, Jack)
Episode highlight: Aaron's birth
#2: Jack's determination to hunt down Locke at the end
