Check out the AVS forums.
They had a thread for my TV, and I used the settings they recommended. When I had the TV calbirated, it was already pretty close to where it was supposed to be. So after paying $200 to have the picture tweaked SLIGHTLY, I'm not really sure it was worth in, IMO.
In fact, the picture was so dark that I couldn't stand it. Anything dark on the screen just became a black blob. I ended up turning up gamma and brightness slightly. Now, I'm pretty much used to it. But the darkness still bugs me once in a while.