Oh Dear! Star Trek: The Slow Motion Picture - that almost turned me off Star Trek forever.
Damn! I've said something negative and that wasn't allowed, but it is true. I didn't bother going to see Wrath of Khan or Search for Spock at the cinema. Which is probably the real reason I like The Voyage Home because it reconnected me once again.
Original series would be The Wrath of Khan. A great, strong story with a brilliant and tearful ending, Ricardo Montalban was brilliant (sure, he hammed it up somewhat but he was awesome), good soundtrack and the Reliant was a cool looking ship that was unmistakably set in the Star Trek Universe. I enjoyed JJ's remake but didn't think it was as good as the original. Second would be undiscovered Country and then maybe the Voyage Home.
The Next Generation is probably Insurrection. Not a popular choice, I'm sure but I thought it had the best story and it was cool to see a darker side of the Federation. The Son' a were good antagonists.
JJ's Trek. I had a soft spot for Star Trek Beyond, which I found very entertaining. Are there any plans for a fourth outing for the new Star Trek team?