I'm looking for the kind of Minecraft server that emphasizes the survival aspect of the game. PvP would be enabled essentially everywhere, with a common sense policy; if you kill someone fairly, don't kill them over and over unless they come back to fight you. In that vein, don't be a dick: If you see someone walking out of spawn or near spawn naked, don't kill them, unless you know them personally and know they have items. 'Spawn' should be defined as the visible area surrounding the spawn point. If you can't see it from the spawn, it's all rules off for PvP.
Stealing from chests would be encouraged; this would require players to combine subterfuge and efficiency to be able to keep their valuables well hidden whilst having them in an easy to reach location.
Structures, however, would have an absolute no-tolerance policy for destruction. Players may not destroy an already existing structure to reach a player, unless that player has built it immediately to prevent assault. In that case, the player may dig through. If a structure has doors or any sort of accessway, the player may enter that structure to pilfer items.