Data becoming human and realizing that he was in love with Tasha Yar in Jean Lorrah’s METAMORPHOSIS is a huge moment in my memory. I also feel struck by scene after scene in Shatner’s THE RETURN. Kirk beats Worf in a fight! Outsmarts Data and Geordi! But falls into Riker’s trap! Also love the scene where Kirk and Picard have a chat once Kirk’s brain is free of Borg programming and Kirk tells Picard that Picard probably didn’t feel as bad as he expected to after the Enterprise-D crashed because it’s not the ship, it’s the mission. I also like PRESERVER where the Kirk/Tiberius scenes are amazing and terrifying and Tiberius is a crazy version of Shatner. COLLISION COURSE asserting that Kirk joined Starfleet to avoid jail and that he first met Spock in a strip club is also hilarious.
Destiny Trilogy really stick out in my mind.. such a world changer. Recently Latter Fire, that was a darn good book, that should be made into an episode or film.. maybe Pike Full Circle set of books.. They actually made me care about Voyager's crew!
The good that men do (the season that never was for ENT...sigh) Vulcan's glory (shows young Spock before he turned robotic) Strangers from the sky (best time travel novel) Sarek (aka a brief history of the Vulcan people before Surak spoiled them) Spock world's (a good sequel to Amok Time) Yesterday's son (aka Spock should have worn a condom,) The Vulcan academy murders (takes place off ship for a change) The IDIC epidemic (see above) The Lost years (a good foundation for why TMP happened) The sorrows of empire (a good sequel for Mirror, Mirror) The Vanguard series (better than TOS in my humble opinion) The New Frontier series (best original novel characters) The Never ending sacrifice (puts a face to the Cardassians and shows how a decision by a main canon character was a huge error) Articles of the Federation (shows there is more to life than Starfleet) Destiny series Myriad universe - A less perfect union (I suspect this is how humanity would behave if dealing with aliens) All of the above I would love to have seen on the small screen
Avatar 1 & 2, by S.D. Perry. It was the story that really sparked my interest in Trek Lit, began my favorite story arc in the DS9 Relaunch and featured an amazing tale with great characters. Runners up: Orion's Hounds, by Christopher L. Bennett, and Articles of the Federation, by KRAD.
I have always loved politics and I loved The West Wing so Articles of the Federation is by far my favorite book, with multiple rereads. I also love the Terok Nor and Eugenics Wars series for how the weave together a variety of bits dropped in from the series and books.
Shatner’s Mirror Universe novels. They were really expect and really the first books to feature characters from. TOS, TNG, DS9 & Voyager.
The VOY novel 'The Murdered Sun' was the first trek book I read as a young teen, i LOVED it and must have read it about 20 times. More recently Destiny, The Fall, Synthesis and Sight Unseen.
I'll second those, i was always disappointed the later novelizations didn't have the same level of additional material. I'll also throw in another vote for The Wounded Sky. Another one I really like is The Galactic Whirlpool. I always liked the slightly harder sci-fi take on Star Trek, as well as seeing some of its concepts adopted into TNG.
Really liked Drastic Measures. It's a Prime Lorca book Spoiler AND has young Kirk in it interacting with Lorca AND Prime Georgio and its not like we're going to get that combo again. Its had quite a bit of reread value to me. Otherwise The Eugenics Wars: The Rise of Khan Noonien Sing. It got me interested in really early Star Trek Lore and it doesn't get too much earlier than this.
I really like the Trek 20th/21st century history that's been built up around the Eugenics Wars, and the MJ12 trilogy.
I have to admit, there are some scenes in the early DS9 Relaunch that played out so vividly for me that there are times where I actually can't remember if it was in a book or an episode.
The strip club part was bonkers, but I really liked the idea that petty thief Jim Kirk was given the choice of joining the academy or going to prison.