Duuude, welcome to the party!! I love SGA, although sadly the crack onscreen is going away (cancelled, oh noes!). Lots of people on my flist are SGA'ers, if you feel like browsing around that way.

I have no pictures, but fic! woo! I can do fic. but non-spoilery, I'm going to have a harder time on that, but I weeeellll trry. Also, I'm pretty much Sheppard/McKay all the way (although McKay is the character of my heart, so I do dabble in McKay/Ronon, McKay/Sam (Carter), and OT4 fic).

-Proof by Contradiction - "What sucked most was the sinking feeling that McKay was handling the whole thing better than he was.": http://intimations.org/fanfic/stargate/contradiction.html
-Transcendental (this is a classic! and longish): http://intimations.org/fanfic/stargate/transcendental.html
-Hindsight (AU!so non-spoilery, I think; sequels on author's page): http://glitterati.talkoncorners.net/fiction/hindsight.php

the fourth vine hits a lot of the classics of the fandom in her recs (also, she's hilarious, if you don't follow her already): http://www.livejournal.com/users/thefourthvine/tag/stargate:%20atlantis

Generally awesome for fic, though can't say all is nonspoilery:
-Cesperanza's fic: http://www.trickster.org/speranza/cesper/atlantis.html
-astolat's fic (start with the older stuff at the bottom for the less spoilery stuff): http://intimations.org/fanfic/#Stargate:%20Atlantis
-rageprufrock's fic: http://glitterati.talkoncorners.net/fiction/index.php#sga
-Polyamorous Recs SGA (select fandom from the menu in upper left): http://bifictionalbedlam.slashcity.net/recs/

You may also want to add the newsletter community (news, ep discussion, stories, vids, etc.): http://community.livejournal.com/sga_newsletter/

Obviously, you have hit a nerve with this one. Let me know if you want to talk/squee SGA, and if you want more specific recs later on (I have other favorites, but I think they're totally spoilery).