I recently watched an episode of "Finding Your Roots", and I was very impressed that Henry Louis Gates Jr. called his one guest, rather than surprising him on camera, to tell him that they discovered something very surprising when they did a DNA test. As a professional genealogist, I recognize that DNA testing for genealogical purposes is a science unto itself, and I prefer to leave it to its own experts. I enjoy the sleuthing through old records and articles to piece together histories.
That said, the engineer in me has to break things down into numbers. Based on the research I have done and my family before me has done on my ancestors, this is my genetic breakdown without DNA testing:
Maybe some day I will have DNA testing done to see if the research matches the test results, but for now I am more than happy to concentrate on telling these ancestors' stories.