Wow...favorite books. I have a few. :)
The Dresden Files - mentioning these because I have seen them mentioned quite a few times in this thread. I actually just picked up the first two about a month ago, and finally fit them in when I was sick last week with the flu. They are good, but they don't rate as favorites. Well-written, entertaining. I'd read the rest if I found them in a used book store, but I won't buy them new, and I won't keep them after I am done.
A Tree Grows in Brooklyn - one of my top two favorites. I read it every year. I can quote the book. This is about a little girl growing up in the depression era, but has such a wonderfully varied and oh-so-real array of characters in it.
Alas, Babylon - my second top favorite book. Another one I read every year. An nuclear war fiction novel. I honestly don't know why I love this book so much, but I do.
Mercedes Lackey - just about anything, but particularly the Valdemar books. I am not a huge fan of some of her earlier works, but all of her work is good.
The Deathgate Cycle - by Margaret Weiss and Tracy Hickman. An amazing fantasy series, strongly recommended.
Stephen Lawhead - anything, but particularly the Pendragon Cycle. Very few books - and even fewer series - can entertain me, educate me, and inspire me all at the same time. This guy is one of them.
A Girl of the Limberlost - this one sat on my shelf for months. I would pick it up and look at it. "Oh, a girl goes to school from selling moths. Boy, that sounds like a fun read" - *puts it back*. Finally I got sick of looking at it and made myself read it. One chapter in and I was hooked, staying up to all odd hours of the night reading. HIGHLY recommended.
Education of a Wandering Man by Louis L'Amour - not a western, but an autobiography. L'Amour was a very intelligent man, extremely well-read. The books he has read, the stories he has to tell - all fascinating.
The Pillars of the Earth - by Ken Follett. Again, on my bookshelf for ages. "Oh, a book about building a cathedral. Fun times." *puts it back* But then a friend recommended it, and I read it, and like with the Girl of the Limberlost I was hooked. I have the sequel, but need to find time to read it. Now that I am on this website, that is likely to be awhile. :)
Those are some of my favorites:)