Help a sister out

goldjadeocean would like to purchase 10 Stargate: Atlantis episodes on iTunes. She wants YOU to tell her which ones are best, over in this post.

I've seen five episodes each of S1 and S2 of Stargate: Atlantis. My experience lines up with what I've been told: it has its moments of brilliance and its moments of "I'm going to pretend that episode NEVER HAPPENED." I don't have anyone local I can hit up for DVDs and I'm not about to shell out for box sets, even if they are on sale.

However!

Through the Magic of Giving (and my brother and sister-in-law), I now have the iTunes wherewithal to purchase ten episodes. And I can see how SG:A could be good--I love moments that play on the characters' competence and loyalty and the quandries they face. I hate the Rodney McKay Is a Clueless Socially Inept Moron show, though I'm increasingly fond of the Rodney McKay Is Not a Brave Man But That Doesn't Stop Him show. I love when John decides everyone else is an idiot and he's going to go do the right thing anyway. I love when Elizabeth has to face a problem she thinks is beyond her. I love when Ronon and Teyla aren't fish out of water, they're competent travellers and warriors.

Given that, what do you think are the ten best episodes of Stargate: Atlantis? Which ones would you recommend I buy? I'd like to get a sampling of all of the seasons (and they're all available on iTunes) to get a cross-section, and things that show the worldbuilding are also useful for fic purposes. I have also, as I've said, seen some already: 1x01-1x05, 2x01-2x04, and 2x17.

Thanks in advance! The more perspectives I get, the better. Also, I totally don't care about spoilers, so feel free to litter the post with them.