Ok, let's have a go (Oh, and I'm doing best to worst cos that's how it works).
1) Star Trek. Awesome film in it's own right, even before it's a Star Trek movie.
2) First Contact. Ditto above.
3) Into Darkness.
4) The Voyage Home. Still feels like the Star Trekiest of all the classic crew movies.
Joint 5th) You can put Wrath of Khan, Undiscovered Country, Final Frontier, Nemesis and Insurrection in here together. I can't pick between 'em. They're all basically alright movies that I'll probably watch when they rock up on the TV - but I don't own them in any format and can't imagine ever specifically wanting to watch any of them.
6) The Search for Spock. Boring.
7) The Motion Picture. Boringer.
8) Generations. Ugh. Ugh to it all. Ugh to the crappy job they did with Data, ugh to killing off Picard's family, ugh to how dull it was, ugh to that bit at the beginning making the new captain of the Enterprise look like a numpty just to big up Super-Kirk. UGH.