Wow, I like what you have done with the circular symbol in all of these designs, it's hard for me to narrow down to just one!
So, we are trying to stay close to the YingYang symbol and #3 comes very close to it with the black circle with the light figure over layed, but unfortunately it also creates a dark feeling to the overall design. I really like the 'glow' of #2. I'm not sure what to call the effect, but i like the gradation of the darker edges to the lighter center in #2.
#4 is an interesting design but I'm not sure I like the 3d effect of the circular image. It looses a feeling of elegance.
I really like #1, it might be my favorite so far, but the image doesn't look quite like a ying yang symbol. But I really like the layout of the text, image and the use of line and color effects.. the image in the center reminds me of a family which is a huge part of our clientele, but the owner does want to see or have the image feel like a yingyang symbol.