Whoops! I'm supposed to put SPOILER WARNING before stuff like that. To all those who saw this in an RSS feed somewhere, sorry!
How many Star Trek movies do not have some element of time travel in them? Seriously, it's getting a little silly. If time travel is so easy, why isn't everyone doing it all the time? Why not go back to when the Vulcans were cavemen and wipe them out then? Why not go back to when the Solar System was forming? (Same question applies to the Terminator: Sarah Connor is so hard to get? Why not kill one of her grandparents? You have four chances there.)
So for the next Trek TV series, here's my half-serious recommendation. Since it seems like half the shows are just excuses to get Star Trek characters to go back in time to Earth (amazingly enough, usually to the year that the episode was written), and since time travel is apparently so easy, why not a series where Federation secret agents are sent back in time to, oh I don't know, early twenty-first century Earth - and they have to combat the machinations of Cardassian or Dominion or Borg or whatever secret agents that are also there, trying to foul up the timelines. Think about it. No fancy sets! Interaction of Federation technology and hapless modern-day humans! Give the people what they want, without a big budget. (Note: after I wrote this I did some research. Turns out the Trek people did try to do this - twice - and it didn't work. Once with the original series with a spinoff with Gary Seven and once with the Temporal Cold War on Star Trek: Enterprise. Apparently it didn't make any fans, although *I* thought the Temporal Cold War was interesting.)
There would have to be some cheesy tech-babble reason why the Dominion couldn't just blow up the Earth or wipe out all humans with some nasty virus. There's the additional issue that we're envisioning in Star Trek a world that presumably never had the Star Trek series. Otherwise in the Borg movie when they go back to 2063, people would say "Wait a second. Star Trek comes true? There's already a whole series of movies about you guys!" (Imagine the location and appearance of your own grave on Stardate 2280.42 and you start to see this artifice a little more clearly.) Then again, if you can get away with people wearing tweed jackets and ties on Battlestar Galactica, this shouldn't be a problem.
But back to the new Star Trek movie - I liked it. Two phasers on kill. I won't give anything else away except that not only is there time travel, we're introduced to a kind of Star Trek alternative history, which I appreciate from a writer's stand point. The Star Trek universe and timeline has very little maneuvering space for a writer. At this stage, it's so fleshed-out and filled-in as to approximate actual history. Does it seem strange that there are, literally, more people in the world who can carry on a conversation in Klingon than in many "real" but endangered native languages? (The Bible and Macbeth were apparently translated into Klingon before they were translated into Ache, a Tupi-Guarani language of Paraguay that a friend of mine speaks fairly well because he's an anthropologist.) Consequently, there's no possibility to add a war or a new species without it seeming senseless that no one has ever bothered to mention, say, Vulcan being destroyed. It would seem almost as silly as historical fiction about the 1893 Canadian invasion of the U.S.
So that's why I like what JJ Abrams did here: he clearly said, let's pay our respects to the franchise, but give ourselves enough room to make a good movie using whatever cheesy plot device we want to. That's the great thing about science fiction - you can use it to bend the structure of the narrative in ways that make the story better - or in the case of the Star Trek franchise, make new stories possible at all.