[Arkshine]

I would say none. For sure ZP or Bio are nice plugins but both have really a boring gameplay, nothing interesting, no suspense, no ambience. A good zombie plugin would be a plugin with an evolution system ( human/zombie ), original weapons and items, missions, intelligent weather system, AI, intelligent ambience, specific and new maps...etc. There are some good idea to sole from L4D. For me theses plugins are just the start. Hope that there will be new zombie plugin more developped.