TMP set a new standard for movie soundtracks when it premiered. I recall that even the critics and fans who panned the film positively gushed over the score.
TFF was a surprisingly good score. I use it for background and RPG music with regularity.
First Contact's score was amazing. I turned to my wife in the theater as the opening credits faded into Picard's dream and told her, "Even if the rest of the film is dreadful, I've had my money's worth!"
TWOK and TSFS were excellent for their time. Unfortunately Horner continued to write for film and now all I can think is, "Oh, look! The starship Titanic just hit the giant space iceberg!"
09 and STID are good scores with a couple of great tracks each, but somehow don't quite sing when listened to without the films.
Insurrection and Nemesis are both far better than the films they accompany.
TVH... Lord, but I hate every aspect of that film. This is the only Trek soundtrack that I no longer own seperately. I cringe at it's 80s bubblegum shallowness.
My favorite piece of Trek music, however, is the intro to DS9. It's the ringtone on my phone!