Star Trek Science and Medical, technically. Blue shirts included Spock, McCoy, and Nurse Chapel (blue skirt, technically).

 It's funny, in that no one on the show ever discussed the shirt colors. In fact, there were a few episodes wherein Kirk would wear an off green number or some other colors. However, officially Gold=large and in charge; blue=science nerd; red=die a horrible death.

When you think about it, though, it was really the blue shirts that did anything. Spock not only saved Kirk and the crew, he is also the only one to kick the crap out of Kirk on multiple occasions. In one of the greatest fight scenes of all time, the Amok Time fight scene, not only does he beat the hell out of Kirk but McCoy, another blue shirt, tricked and drugged him. So if you want to be the power behind the throne, this is the shirt for you.