What's in a Name?

I recently had an interesting discussion with my critique partner about naming our characters. How do we authors come up with names? Do we just go through a book of baby names, and come up with something we like?
When writing historicals, we obviously need to choose names that fit the time period.
For me, when I wrote Yellowstone Heart Song, it was a no brainer what my hero's name would be. Daniel, or the variation Nathaniel, was a popular name in the 1700's, and 1800's. It was also the name of a favorite character of mine from a book I once read. My heroine, Aimee, is a modern woman, so I was able to choose pretty much anything. I like the variation in the spelling from Amy to Aimee, but the pronunciation is the same.
In Book 2, Yellowstone Redemption, my hero is a modern man, so I chose the modern name Chase Russell. I "borrowed" the name from a contemporary story I had been working on (but have abandoned), with the intent of changing it later, but it stuck. The heroine for Book 2 needed a period name, and Sarah seemed appropriate.
Now for last names. It took me a while to come up with a last name for Daniel. Finally, the answer stared me in the face. I was reading a book (for research purposes) written by a 19th century trapper in the Rocky Mountains. This man's journal is one of the most complete accounts of a trapper's life, and a fascinating read. The book is called Journal of a Trapper, and his name was Osborne Russell. I had my last name for Daniel, and subsequently a last name for the next hero as well.