It used to be easy to kill the Dock, but Apple made it harder with 10.5, disabling the hidden options that, under Tiger, had made it possible to remove their annoying error.
I love my Mac, but this is a fairly typical Apple shortcoming, a weird control-freak mentality that blocks you from truly owning your own machine.
Currently, this is the closest thing to a Dock-killer I know:
#make dock really really small
defaults write com.apple.dock tilesize -int 1
To use it, you also need to set the Dock to auto-hide and turn magnification off.
Still not perfect, but much better.