Tough one. I'd say my 75-80 mph out wide slice serve on the deuce side that catches the sideline. Even if my opponent gets to the ball, I drill a crosscourt bh into the open court. If s/he catches on and cheats out wide, I just blast a flat one down the T.
My latest video: https://www.youtube.com/watch?v=gydD9HS0DOw