I...have so many favourite books! So many! Well.
The Watch series are very good, though i've only read Night and Day, i'm eagerly awaiting Twilight.
Terry Pratchetts Discworld books are also among my favourites, especially Night Watch (no connection to above Night Watch) and Thud!, them being among the more poignant books for me at times.
Leon Uris' Trinity and Redemption are also masterpieces.
Bernard Cornwell is well worth reading if you are of a historical disposition like myself.
Walter Macken has some great, touching books, any work of his is my instant favourite.
Everyone here should have read J.R.R. Tolkeins Lord of the Rings and The Hobbit, so I do not need to explain it.