Had to go with Meyer. While I feel TUC itself is somewhat overrated, I do feel that Meyer overall gave us the best mix of character, intrigue, and action.
Wise gave us a fully formed future reality, though rather sterile and lacking in the very humanity the story tried to embrace. I place the blame more on Roddenberry's evolving image of the future he was trying to write about, but Wise was at the helm directing the actors. I adore the film, but not my favorite direction (editing did no favors here either)
TWOK came with a literal vengeance, retaking the pace, the fun, the humanity and the foibles of our beloved crew. Still my favorite film of the series, although far from the most technically advanced or deepest of story lines, this gave us a simultaneously vulnerable and pompous Kirk.
Nimoy's outings contributed great character, respect for the original series and a wonderful romp with TVH. Understated, proficient, and very impressive for a freshman director.
Shatner -- what can I say, boundless enthusiasm but never bought the story, the guest aliens or the Kirk/Spock dynamic here. This is a cartoon. Some moments of interest, but not a cohesive whole. The budget may be partially to blame, but it is also the director's job to work within the limits set by TPTB (see TWOK)
Carson did a good job with the script he was handed. The Ent-D never looked better and again there are some nice moments, but nothing to break free of the cookie-cutter script.
Frakes gave us all the enthusiasm Shatner had, but worked much more successfully within the scope of the productions he was given. Talented, assured, and very well-done, that is till he was handed the mess that INS became.
Baird can handle action schlock, but please stay far, far away from ST
Abrams has brought the series into the 21st century of big-budget, big-action movie making and does an impeccable job at it. Financially successful, well received by the larger audience, pays homage to the trappings of TOS, but, like Shatner, is making cartoons, just highly entertaining, incredibly polished, very fun cartoons