Numerology, by Random
Remember in "Redemption," when Hammond and Jack discuss how many people Jack's gone through trying to get a new 4th member for SG-1? This is the story of those nine hapless replacements, and why none of them worked for the team; but it also extends into season 7, and is the story of how Daniel felt trying to slot back into a place he only vaguely knows that he once occupied.
Well-written, angsty, and true to the characters (all of them, but especially Jack and Daniel), with some humor (like the betting pool the rest of the SGC has going) thrown in to blunt the edge.
You Can't Always Get What You Want, by Betacandy
This fic is extremely difficult to write a summary for, and even trying to do so is making me grin like a lunatic. Basically, this fic is what happens to Daniel and the alt-timeline Jack-Sam-Teal'c who went back to Ancient Egypt in "Moebius." If you were weirded out by the time travel, or wondered whether these other versions of SG-1 lived on after fixing the timeline, you need to read this.
I'm tempted to label it crack!fic, except...given that "Moebius" is canon, this fic is also strictly (and occasionally heart-wrenchingly) canon. Which is just...*sporfle* Character angst and gigglefits in equal meansure. Go and read! Now!
And for those who stopped watching after Daniel's death (though Daniel features prominently in both of the previous recs):
Salt of the Earth, by ELG
Here's the author's summary:
Deeply affected by the events of ‘2001’ and ‘Between Two Fires’, Sam begins to question everything, including her own judgment. When SG-1 find a breakaway community of the Tollan who have apparently sabotaged the crops of the indigenous population Sam is ready to believe the worst. But are her suspicions justified?
I can't really put it any better than that. There's a solid mystery, some suspense, and intriguing role-reversals within the team as events separate Jack and Daniel from Carter and Teal'c. Being an ELG fic, there is a bit of overkill in the introspection department, but this has much less than other ELG fics I've read, and given that a lot of the angst is Sam's, and I've never seen her mindset at this time in the series explored so awesomely, I really didn't mind. :-)
A serious thumbs-up from me.
ETA: Assess This, by Betacandy.
This fic is post-"Emancipation," i.e. very early season one, and has become part of my personal show canon. Janet Fraiser meets SG-1 during her third day at the [loony bin] SGC. Mostly funny. :-)
Enjoy, all. :-) (And many thanks to sg_fignewton for pointing me to these.)