Cellar, steel-door with face-detection. Only if me (and/or wifey) are present the door opens shortly, video-surveillance, alarm-system. Same for gate and entrance. So you first would have to make your way TO the server-room :-) Might be an overkill (who wants to steal a server?!) but our backups and archives are stored there too, 100% fire-proof. And I value those. Money is replaceable.