I'd like to see something like this.

I never liked the look of the old or 'other' sentry gun, plus there's a few more types I'd like to see :
Team 1 Type : Fires only at the other teams.
Team 2 Type : Fires only at the other teams.
Team 3 Type : Fires only at the other teams.
Team 4 Type : Fires only at the other teams.
Zombie Type : I know we have this, but putting things twice in one thing and once for the other, never does wrong.
Bot Type : Fires at bots only.
FFA Type : Fires at all players EXCEPT the spawner (maybe spawned by a tool).
FFA Type 2 : Fires at all players, including the spawner.
FFA Type 3 : Fires at everything, excluding vehicles.
Vehicle Type 1 : Fires only at land vehicles.
Vehicle Type 2 : Fires only at aircraft (flying) vehicles
Vehicle Type 3 : Fires at any vehicle.