Back in the days of LANing 8-12 of my closest friends and playing massive amounts of Mod and "honest to god" DoD(Day of Defeat) there was nothing more satisifing than a trench shovel death (yea i know my spelling sucks, bite me). The shouts of joy and victorious arm pumpage followed by a few words of wisdom from the victim was most satisifing.
If one could keep a trenching shovel sharp enough for multiple kills this would be my choice, but as posted before the crowbar is the most functional and i would say falls under the improved axe listings.