Without any doubt
Sprinta.
The layout of that map is so simple, and yet so well thought.
Jails in the middle, where from jail can see the other players walk over and under you.
The one redeemer easy reachable for all players.
The guns and ammo at exactly the right place.
The upgoing release button leading to the UDamage.
The terrific jail death sequence, with the heavy music and the shaking screen.
This map is a classic already (at least in my opinion).
I even think about taking this one with me to my deserted island.