Spiritual guides

Every meditation class or Reiki session I have attended, people always talk about spirit guides. I have always understood (or felt) that my guidance came from my own soul whose source was the collective soul. I understand archetypes and often use these in meditation but cannot fathom spirit guides. Are they archetypes? Are they other souls helping us? Why does everyone have an American Indian guide? Friends have even had theirs drawn by an artist, not sure how I feel about this. Where do you stand?