I just saw the movie last night and am still "coming down" from it. I was totally sucked into the movie from the first second and the movie didn't lose my attention once until the end credits. Plus my wife and I saw it at the IMAX, which made it better- at moments during the film (i.e. the space battles), it felt like we were moving along with the ships, particularly during the opening battle scene with the Kelvin.
The fact that that movie was a "reboot" and totally unaffiliated with the established continuity of the original Star Trek series was kind of jarring and hard to get used to at first, particularly having Leonard Nimoy portray the older Spock in the same identical way that he portrayed Spock in TOS and TNG but after a while I got used to it and accepted it. There were tons of subtle nods and homages to TOS and all of the new actors and actresses did a great job IMHO of representing their characters, particularly Pine as Kirk, Quinto as Spock, and Urban as McCoy. They all totally nailed their roles for me.
Admittedly, there ARE a lot of things in the movie that require some pretty significant suspensions of belief, the most obvious being Kirk's metoric rise from being a Cadet to Captain (at age........?) by the end of the movie but then again, he DID save Earth and he IS James-Freaking-Kirk, so I guess that's got to count for something. How he wrested control of the Enterprise from Spock seemed a bit underhanded and scheming but Spock couldn't have been (and obviously wasn't) as stable as he needed to be in order to perform his duties as Captain "admirably" after the destruction of his homeworld and the death of his mother (played, incidentally, by a remarkably well disguised Winona Ryder). Although, such things have happened on TOS (i.e. "The Enterprise Incident") so I guess there is some precedent for such a situation.
Nero, while not a "Khan-caliber" villian was at least much improved from some of the more recent Trek villians and certainly better than the last villian, Shinzon. Nero's grievances seemed realistic and his actions in this movie at least made more sense than Shinzon's in "Nemesis".
The special effects were excellent as expected. I loved the more fluid movements of the ships when compared to TOS. The only similar comparison from the original Trek series I can think of offhand was the battle against the Borg at the beginning of "First Contact." Whenever there was a battle scene, it felt more like watching a space battle from, say, "Star Wars" rather than Star Trek (which is a GOOD thing, in my book).
Michael Giacchino composed an excellent score for the movie. During the scene where Kirk is stranded on Delta Vega, his score sounded highly reminiscent of the composers for TOS and he, of course, incorporated Alexander Courage's famous theme from TOS into the end credits weaving it together with the newer aggressive action score.
All in all, I LOVED the film and I'm very satisfied with how it turned out despite having had some initial reservations about the whole idea of a "reboot". It seems as though Abrams has successfully managed to breathe new life into the franchise and I sincerely hope the new Trek lives long and prospers!