Wow, another tough one. I love, love, love to read. So picking a favorite book is hard!
I love many of the classics - Sense and Sensibility, Pride and Prejudice, Great Expectations, Gone with the Wind, etc.
I love fun chick lit - the Shopoholic Series, books by Meg Cabot.
I love Christian fiction - books by Lori Wick, Kristen Billerbeck, Dee Henderson, Terri Blackstock.
I love books that I feel help me grow in my Christian Walk - anything by A.W. Tozer, David Ravenhill, Bob Sorge, John Burton.
I love books that teach me how to do things I've always wanted to do but can't - cook, for example.
I also have book A.D.D. I'm usually reading 3-4 books at any given time, and I'll read different ones different days depending on my mood and how much time I have to devote to reading at that moment. But once I start a book, I HAVE to finish it. Even if I don't like it.... even if it takes me a year.... even if I have trouble going back to reading it. It's a compulsion. There have been exceptions (hello, Eat, Pray, Love) but generally, I finish any books I start.
Right now, I'm in the middle of Radical by David Platt (wow. this book is a must read!), Six Enemies of Fulfilled Destiny by John Burton, Pretense by Lori Wick, and of course, the Bible.
Speaking of Pretense, something else I do is re-read a same book over and over if I really like it. Pretense is an example of this! I first read it probably 10 years ago!