Massive Trekkie here - been into it since I was a kid in the early 80's watching re runs of the 60's show, The Motion Picture was the first film I ever saw at the flicks and that sealed the deal - even to this day the flyby of the Enterprise in space dock gives me goosebumps. The Wrath of Khan is the best of the movies for me though, followed by (and I know no-one will agree with me) Nemesis, First Contact, The Undiscovered Country, The Voyage Home, The Search for Spock, the Motion Picture, Generations, Insurrection, and The Final Frontier, which I think is the only genuinely bad movie in the series (though it still has a few good moments). The 2009 movie I thought was excellent, very entertaining, some great casting and despite the time travel elements to the plot (which I normally dislike) a very neat way to reboot the franchise. I can see why some fanboys dislike it but I thought it was a job well done and can't wait for next year's sequel.
Series wise, the original series is just too old and dated for me to really enjoy it any more, The Next Generation was awesome (from season 3 onwards bar a couple of episodes), DS9 was the most entertaining for me though, especially the last couple of seasons with the Dominion War, enjoyed Voyager immensely too, and thought Enterprise was criminally underrated also