The hinge trigger
The hinge trigger that has impressed me the most is the Planet Eclipse hinge trigger! I've tried several different hinges, but the Eclipse is soooo awesome, waaaay too awesome! I've let others who used different hinge triggers try mine's and they are totally impressed. Why?
Because it's very comfortable (wide Blade Trigger), angled perfectly, super smooth, and allows you to shoot really fast. You should try it out someday... just look around for someone who has it installed on their Autococker/STO/Black Magic/etc.
Btw, they're on sale for $89 at Paintballgateway.com