By Margaret Lyons
Updated September 21, 2009 at 10:14 PM EDT

I watched a preview of tonight’s season premiere of House, and without giving anything away, I can say that it’s really, really good. I loved it, and I hope you love it — but nothing will ever come close to season 1’s “Three Stories” for me. That was the episode where House went from being a show I liked to a show I loved, from being good to proving it had the capacity to be great. I think of these as time capsule episodes, the ones I’d want future societies to see so they could think “my my, this ancient civilization had marvelous taste and popular art.” It’s the episode where a series really plants its flag and says, “no, this is what our show is about.” For example…

Big Love, “Come Ye Saints”

I was lukewarm on the first season of BL, liked the second season enough, but this third-season episode cut me in half, and proved that Big Love was still discovering compelling — and grounded — emotional storylines. Amanda Seyfried, Chloë Sevigny, and Jeanne Tripplehorn turned in stellar performances and completely refocused the emotional engine of the series. I defy you to watch the last four minutes of this clip and not lose it:

Friday Night Lights, “Mud Bowl”

I’m hard pressed to pick one episode from the knock-out first season of FNL, but the aaaaaalmost-schmaltzy “Mud Bowl” demonstrated what the show was capable of doing: making corny ideas not corny at all. Oh, they’re going to play in the rain, and let their spirits shine, and be the kind of young men the noble Coach Taylor has taught them to be through his sound leadership and ethical decency? I…would very much enjoy watching that. Throw in a thwarted rape and I am there!

The Office, “Casino Night”

It’s not the first good episode of The Office — the second episode, “Diversity Day” was a treat and a half — and it’s not the first emotional episode (“Booze Cruise” had some holy-crap moments). But “Casino Night” was when The Office really arrived, when every character clicked into place, when the plot swept everything towards an inevitable but still glowing conclusion.

The Big Bang Theory, “The Bath Item Gift Hypothesis”

BBT started finding its rhythm most of the way through its first season, with a dead-on finale proving they’d found their game. The second season was even better, as the show started letting a little more warmth into its characters and their relationships, reflecting the affection audiences were feeling. But it was a very special holiday episode, with Penny’s almost-too-perfect gift to Sheldon, that locked BBT in for me; If Penny’s sort of the fish out of water on the show, the Nemoy napkin proved she — and we — had learned to swim.

PopWatchers, I am barely scratching the surface of my list — I haven’t even touched shows that aren’t on anymore. So let’s flesh it out: What’s the episode where you fell in love?