I'm choosing column 4 because:
1. It creates a two-piece horizontal sequence with my existing O piece (in columns 3 and 4)
2. It begins to control the center of the board, which offers more winning paths
3. It prevents my opponent from potentially building off their X piece horizontally in that direction
4. It doesn't create an immediate setup for my opponent by placing a piece directly above the existing pieces

This move both advances my position toward potential horizontal, vertical and diagonal winning paths while maintaining good board control.