I have heard of some people say that when hanging tile on walls that youuse ceramic tile adhesive instead of thinset mortar. But they say go ahead use thin set on the floor. Does anyone know if it is better to use adhesive on walls??

Use a good tile adhesive, most tilers(in Australia) use adhesive on the floors too.
They put a sand and cement bed down first, with the correct falls, and wait till it is dry, then glue the tiles down.
It is a much better way to stick your tiles on, as it allows for some movement between the wall/floor and the tile. e.g.. Expansion and contraction.

Your wall material should be a modified acrylic thinset, it looks more like creamu paste than mortar. On the flood you use plain thinset if setting tile on concrete. If you setting on a sub floor like plywoood or Hardibacker then use modified thinset again.We do not use adhesive with ceramic or prcelein, only with vinyl and rubber.