I voted for "The Final Frontier", since the poll asks "favorite", not "best".
"The Voyage Home"is the best executed film with the sharpest script,
but "The Final Frontier" is my favorite; I get what Shatner was trying to achieve. I get this film isn't for people who like their Trek more serious, and nerdy, and thats cool. But for fans like me who enjoy the Kirk-Spock-McCoy interaction of TOS, a certain campiness along with the attempt to say something meaningful---this is up our alley. I dont care if Bran Farren or ILM is doing the effects. I think this is how Shatner 'saw' "Star Trek", and yes, it was the way Star Trek used to be with TOS. Of course, as TNG progressed, Star Trek changed a lot, with techno babble and rigidity. But "The Final Frontier" harkens back to the TOS brand of fun that probably will never be "in style" again.