Who sat in the seats at a greek theatre?
During contests and celebrations, everyone could attend the theatre as the state covered the costs of tickets for spectators. This meant that peasants could attend the presentations. There was special seating at the front of the theatron reserved for the most important spectators, such as officials and priests, and for the most honourable spectator, the priest of Elefthreos Dionysus. Judges were also involved, as they would choose winning plays depending on the rest of the audience's reactions.
At the front (more detailed description below but if you want something quick there it is) *Well it says in the Cambridge Latin Course book (1) that they sat in the best seats at the front of the theatre with an other important citizens, these seats were reserved for them so they did not have to rush.*
It depends on what your definition of a good seat is. In the days of the Globe Theatre, the floor seats closest to the stage were the cheapest seats. The further one sat in the Globe, the more expensive the seats as opposed to today where the close seats are more expensive. In order to get a far away "good" seat, one usually had to be a member of the aristocracy.
The cheapest place to watch a play in the Globe Theatre was actually the "Pit," which is where most people stood. The "Pit" was the area around the stage where people could just gather around. It cost only a penny to get in to see the play, and those who could afford it sat in covered seats, but those seats were more expensive.