The 'Big Three' were all portrayed extremely well - so well I can scarcely pick between them. Overall, I'd say Urban's McCoy just pipped Pine's Kirk at the finish line, but Pine absolutely nailed Kirk's can-do arrogance. "Bull****!"
Of the rest... Greenwood's Pike was sensational - as I was expecting! - and I thought Cho's Sulu hit all the right buttons (except the one releasing the parking brake, that is). It was really nice to see him kicking serious Romulan arse on the drilling platform after all those years of simply sitting and sweating at the helm...
Loved Saldana's Uhura, too.
Of course, it goes without saying that Nimoy was great, as always. I'd actually like to give a shout out for Eric Bana - my only complaint about the movie was that we didn't get enough Nero Time. "Hi, Christopher!"