Wow there are many happy hammockers out there! I'm a ground dweller myself, we seem to be under represented!
To be honest hammocking never occured to me as most of my trips are by myself and i never realised they were an option. However i met up with a local bushcrafter recently who happened to use a hammock and he showed me the ropes (sorry I couldn't resist) I used a tarp and bivi for a long distance walk across scotland this summer and now I have all the kit I'll probably stay on the ground.
Here is a set up I used on a trip into the caledonian forest early this summer:
I use a waterproofed cotton tatonka tarp. If i'm staying in place for more than one night and if there are materials handy, I construct a bed like in the photo. Otherwise I just quickly line the ground with some vegetation, eg bracken, spruce bows or heather to keep the mud off the bottom of my kit and the bottom of my bivi. I find this to be especially necessary if it's raining while I set up, or if it has been raining recently...things can get muddy pretty quickly if you are directly on the wet ground.
But the biggest reason for me to stay on the ground is to have a fire burning nearby through the night, especially a long log fire when its cold.
(anyone know why the picture came out so small? (i'm new to the forum)