starwolf said:Well Clay, personally I think the answer will lie somewhat in what how you envision the interaction of the spirits and spirit world in your campaign. But I will try to give you some suggestions and how they operate.
If the spirits are strictly an abstract concept and flavor for your world then you may want to check out the shaman from Oriental Adventures.
If you envision the shaman in semi-native american tradition, with a lot of wilderness trappings and where the spirits are encountered are mostly antagonistic then check out Green Ronins version in The Shamans Handbook.
If you envision the shaman in a psuedo-siberian or old world tradition, and the spirits have more of an interaction and personality (both friendly and antagonistic) then you may want to go with the Mongoose version in Shaman's.