Right now, no mode. Car's in storage for the winter
Usually, S5 mode for everyday driving in the city and highway, and S6 + Sport mode for having fun.
Agree with the above that modes 1-4 are pretty slow to shift and unless you're having traction problems or learning the car in the first few days / trying to resist not gunning it while you're breaking in the engine, I'm sure that most people that bought the ///M in the first place wouldn't bother with these.