I like Wrath of Khan. It's pure quality. Plays out like a submarine movie in space. Least favorite would have to be the Motion Picture. Not just for the plot being boring, BUT also because the uniforms look like they belong in a gay 70s disco, not on a futuristic starship.
Final Frontier is in the middle, for several reasons. 1, it's written and directed by Shatner, which means that it takes place in the Shatnerverse. It has to be taken as campy, because that's how Shatner writes. The story was kind of really crappy (the center of the galaxy in a matter of days?), not to mention the anti-religious sentiment. BUT, the banter between the characters is awesome, especially between Bones and Spock. The constant ribbing feels like the old TV show, and you can tell that Shatner has love for all these characters.
As for TNG, hands down First Contact is the best. Generations was kinda lame, Insurrection felt more like a TV episode, and Nemesis I liked despite the continuity errors.
I will probably get alot of grief for this, but I also really love Star Trek Enterprise. Bakula fit into that era of Trek very well, with his curiousity and cavalier attitude. He seemed like a good fit for the role. I would have loved to see the Romulan War played out, but alas, it was not to be. Season 4, as truncated as it was, fit alot of pieces into place for Trek history (the Orions, Eugenics, Klingons with no forehead ridges, Doctor Soong's ancestor, the Borg, etc)