What's in your DNA?

I have recently received my Ancestry.com DNA kit in the mail. Soon I will spit into a tube and send off my bodily fluids to be analyzed. There are other choices for DNA analysis, like the National Geographic option, that may be more detailed and encompassing, but I talked to a friend and she said her first and cheaper choice was the Ancestry.com offer. If the Ancestry.com results are tantalizing and bring more questions and curiosity, then I'll likely go for the National Geographic analysis too, and will probably try to get my father to submit. Before I get the results, I thought I would write about my expectations. What surprises might there be? What will unlikely be a surprise at all? 
Expected:

• I would expect that about 60 percent of my DNA ancestry should be from the British Isles-- England and Ireland. 
• I know I have some Scandinavian DNA. 
• I'm probably all Northern European.

Surprises or Questions to be answered: 

• Do I have any German ancestry? Was my great-grandfather on my father's side, David Miller Taylor, German? 
• Do I have any Native American blood? Did my great-grandmother Jedidah Pinhorn have an indigenous female relative in Canada?
•  Do I have French ancestry? Perhaps? 
•  Can the DNA test tell me how far back my Norwegian ancestry goes? 
• It would be a real shocker if I had Asian or African American blood, but you never know.  
• Were my ancestors ancient Druids? 

I don't know if DNA analysis will tell you anything more than what you can research in documents. I suppose it should, since DNA should go back before people kept records. We shall see.....