(3) Zachery Quinto does a nice job as Spock, but he can't hold a candle to Leonard Nimoy. Perhaps not that original of an observation, but I'm blown away by Nimoy's portray of Spock.
When a character is that minimal, the tiny artistic choices an actor makes are really pushed to the foreground.
It's amazing how Nimoy conveys such a memorable character with just a tilt of the head, a narrowing of the eyes, or other little details like that.
These characters, for the most part, defined the actors' careers as well as the reverse.
The fact that Shatner (I almost typed 'Kirk') was able to move on to other things and redefine his career as he went is a tribute to his ability as an actor.
Nimoy never really got past Spock, and the other original cast have not gotten past those roles either.
IMO, YMMV, whatever.