There are so many excellent books out there worthy of discusion that I never really know how I can write about just one. So I thought I would just write a line about a few of the very best in different genres - and this is by no means all of them!
The Lord of the Rings (Tolkien)- what can I say? Brilliant! (that's the best I can say about a book) It's quite Catholic if you get into details.
Percy Jackson and the Olympians (Riordan)- Brilliant conception, great writing, can't wait for the sequel. The series is about a modern boy who discovers he's a greek demi-god.
The Belgariad (Eddings)- Brilliant characterisation and a good story. Without the characters it would just be a good book, as it is it's incredible.
A Wrinkle in Time (L'Engle)- Brilliant! Quite different, but I empathise with Meggie. An exploration of ideas like the 5th dimension combined with a perceptive view of a geeky (?) teen.
I, Robot (Asimov)- No, it's not just a movie. Stunning book. Interesting to note that Asimov doesn't use much humour.
Christian Fiction (I'm not into romances, so these could be in the previous categories)
Dragonspell (Paul) -Excellent book, I like the imagery. It's allegorically without being syrupy. Good story.
The Cosmic Trilogy (Lewis)- Well, Lewis is probably my most respected author. Interplanetary travel introduces Ransom to the heavenly beings. It gets very dark towards the end as well as plain confusing, but has a solid story line. Very thought-provoking.
The Chronicles of Narnia (Lewis again)- I've read them about a million times, starting from age 4. They're like comfort food except good for you.
Those are the best that spring to mind now. Tomorrow I'd write a different list. I haven't put my favourite classics down, for instance. I'll extend the list another day.