Playing in column 4 is my best strategic move for several reasons:

1. It builds on my existing vertical pieces - I already have an O at position (4,4), and placing another O at (3,4) creates a vertical two-in-a-row.

2. It prevents a potential future threat - if I don't play here, my opponent could place an X at (3,4) on their next turn, creating a potential vertical threat with the X at (5,4).

3. It maintains control of the center of the board, which generally provides more flexibility and opportunities for future connections.

4. It could contribute to diagonal winning opportunities in future moves.

While there's no immediate threat to block or winning opportunity to capitalize on in this turn, this move sets up the best position for future success.