Let me just say that I LOVE getting and giving books for Christmas and for years, because I owned a bookstore, I never got any. (I mean, other than the hundreds I bought myself!) I no longer own a bookstore but still I get very few books, probably because I read so much no one dares get me anything.
Although last year for my birthday my husband bought me My Last Supper by Melanie Dunea. It's a great coffee table book if you love food as much as I do (which comes in a very close second to books, so books about food are always an excellent thing in my mind). It's a really beautiful, if not slightly morbid, collection of chef's and other foodies' imagined last meal, complete with recipes.
I love giving books. It may be a little late for this but you can always scurry out to your local bookstore and see if they have these titles:
For kids and tweens: The boxed set (if you can find it) of The Chronicles of Narnia. I still remember getting it for Christmas from my mother's cousin--I must have been about seven. I remember burrowing under my covers and reading the whole set start to finish, and then reading it again. Maybe this isn't the hottest new thing kids are into, but if you've got a kid who loves fantasy-type books and they haven't read it, I'd bet it would be well-received.
For my mom: I like a well-written mystery, one that is character-driven and not too gory. I like Julia Spencer-Fleming's series which start with In the Bleak Midwinter.
For my husband: Who likes true-crime stuff, I like Howie Carr's The Brother's Bulger. About Whitey and his gang, it's a great read.
For anyone who likes to cook: My favorite, most-used cookbook is The Joy of Cooking. You can't go wrong with a classic.
Speaking of which, I would give a classic like To Kill a Mockingbird or Middlemarch to just about anyone.
And if you know someone who writes, or wants to write, my favorite is by far Anne Lamott's Bird by Bird.
I'm sure I'm forgetting many of my favorites to give and get. I'd love to hear your suggestions!
Of course, a gift certificate to your local bookstore is always good, too!