For my walls, I am currently considering 1/8" luan (exterior glue) over 1x framing and insulation, and 1/2" oak plywood for the interior skin. I like to woody look, but the cost of exterior plywood is very high.
If you are using 1" framing, then you certainly do NOT need 1/2" interior skins!! 1/4" on one side (I would suggest the outside) and 1/8" on the other side (reccomend inside) would be plenty for strength. Also, I am assuming that you are actually using 3/4" framing that is commonly called 1". Anyway, be sure to put insulation in the walls to keep the heat (and the cold) out.