Personally I would like Abrams to talk Spielberg into doing Star Trek. I can see a press conference in 12months or so with JJ announcing that he will step down from the directors chair due to his commitment to Star Wars but talked his friend into taking over from him
That would be awesome. Spielberg is still the king!
Nick Meyer? I think he would be the first to admit there is no way he could helm a production like Star Trek what with all the green screen and effects considerations of today. Michael Bay might get some stick from the internet but his films are technically brilliant and the shots he sets up are very very complex! No one comes close to Bay in this regard imho... stay away from Trek though Bay!
I think the most likely director though will be Brad Bird.