My TWO HANDS.
No really, I use the standard Lesche. It is a very solid digging tool, but I think that it is a little lacking for some tasks. I think that it is good for digging soft soil, or even working in gravel, but can be a little lacking in hard ground or cutting through tough grass. I am still looking for the best tool and I am trying to "talk" myself into trying/buying the Raptor by Predator Tools.
The Sampson is the best for breaking ground but not the best for moving a lot of dirt. I have a Lesche Ground Shark with the "D" handle that is tops for moving a lot of soil.
My assumption is that there isn't one perfect tool for everything, but I like the Lesche shovels so far. I am sure that all the Predator tools do a good job in their own right, but I can't bring myself to pay $80+ for a shovel just yet.