Best cinegamma setting for hd100
 

What setting for cinegamma do you guys think yields the most filmic image? What do you guys use?

It depends what you consider to be "filmic." It is very subjective and hence hard to answer.

If you are looking for film-like gamma response, then use the cine gamma curve. If you are looking for as much dynamic range as possible, lower the knee and stretch the blacks.
Colour-wise, experiment with the scene files available, and don't be afraid to play with the settings. Many people have achieved a pretty close "Kodak" look with my "WARM" scene file. You may want to try that as well.

what number setting would you set the cinema gamma at?

I set it to -3 for most of the last film I shot. That doesn't necessarily mean you should. Testing is the best bet.
I've done alot of testing under different conditions and for the most part I was using completely controlled lighting, and I carefully controlled my ratios.