I am taking a cue from Angieville and stepping back to think about what books I'm really thankful for! I have a number of books that are near and dear to my heart.
Hop on Pop by Dr. Suess: The very first book I ever read on my own. This is the book that started it all :-)
The Hobbit by J.R.R. Tolkien: When I was a little girl my dad would read me and my sister and illustrated version of The Hobbit. I loved it and was absolutely enchanted by it and it helped set the course for my lifelong reading preferences.
The Wonderful World of Oz by L. Frank Baum: My mother read the OZ series to me and my sister as we were growing up. This was another set of books that absolutely made me love fantasy.
The Hero and the Crown by Robin McKinley: The first fantasy book I purchased and read on my own. I loved it, I fell in love with the wonderful characters and the determined young girl who worked so hard to succeed.
By the Sword by Mercedes Lackey: When I meet my husband in high school we were both reading this book. It was part of what brought us together as friends and I am grateful that it helped draw us together. This also led me to reading The Last Herald Mage series which was a wonderful series and my first intro to GLBT literature.
The Eye of the World(Wheel of Time, book 1) by Robert Jordan: This was the first epic fantasy series I ever read and it was/is fantastic. In high school me and a couple of my girlfriends dedicated a good portion of our lives to this series. I am still reading it and excited for its conclusion.
Moonheart by Charles DeLint: The first urban fantasy I ever read. This is responsible for my delving into urban fantasy and for the love I have for that sub-genre.
Neverwhere by Neil Gaiman: The first Gaiman book I read. It opened my eye's to the wonderful world of Neil Gaiman and the wonders of urban fantasy.
The Sleep Book by Dr. Suess: I read this book to my son a billion times during the first couple years of his life and it will always bring back wonderful memories (as well as memories of sleep-deprivation).
The Bravest Knight by Mercer Mayer: A wonderful little book that introduced my son to knights, castles, fair ladies, trolls, and irony. Great little book, that we read with my son obsessively from the ages of 2-3.