Parking brake left set.
In the fifty and some years that I have been involved in aviation, as a ground engineer, flight engineer and pilot I cannot ever recall a normal requirement to leave the brakes applied after having the chocks in place. That applies to all the aircraft I have been associated with from light aircraft to B747's. I am not questioning the posts of those such as mudackace or Feather #3, just a little surprised that their company uses such practice.
It is odd but true. The only operator I have worked for that left the brakes set hot. We have no brake issues. I believe it is policy because of the 727's lack of hydrolock on the nosewheel steering as an additional measure to prevent the aircraft from spinning around in strong winds (they will jump chocks).
On another note it has been common practice in the past on all aircraft I have ever worked with to leave the brakes set during a layover (after they have cooled down). We do not practice this on other fleet types at my current employer.