Let's see... I've read so many fantastic fics over the years (thanks to House of Tucker) that it's hard to pick a small sampling.
I do find that I tend to re-read these fics that have been around for a while, however:
HopefulRomantic's
Reconnecting Series. It becomes AU (season 4) but it's well worth the ride. I've always loved her development of "The Family" and her take on Archer. (I won't lie -- it's sometimes hard to find in TnT fic where Archer isn't painted in a negative light. I happen to like the character, myself... flaws and all.)
MissAnthropic's
Cry Havoc. Yes, just as
JediKatie mentioned... AU season 3 and simply amazing.
And of course,
THE Rigil Kent's
Endeavor Series.
Those should have been our relaunch novels as far as I'm concerned. Mr. Kent is one of the most polished authors I've read in ENT fanfic. Tell me again why you aren't published yet??
New gems by authors newer to the fandom that I can't get enough of:
Alelou's Missing Scenes Series (
season 1,
season 2, and
season 3) She's currently up to "The Hatchery" of season 3. I love how she inserts realistic T/T moments in every episode and seeing the development of their friendship as well as something deeper throughout the series without harming canon.
Transwarp's
The Tucker Chronicles: 2155-2160. However, I will admit that I feel like the series really hits its stride with "
Command" so don't come after me with pitchforks if you find yourself not "wowed" with the first two stories. :p I like his take on the Romulan war, which is different than
Rigil's. (I like BOTH versions.)
BlueTiger's
Keep Your Enemies Closer and
Is This Any Way to Run a Railroad?... because... I have a crush on Morgan Tucker. A huge, huge crush on him. He's all kinds of awesomesauce!
And I'll read anything by
Aquarius and
Honeybee.
There are so many others that I love, but this is what came off the top of my head.