My suggestions for Advent reading are always the same:
Life of Christ, by Fulton Sheen
To Know Christ Jesus, by Frank Sheed
You will be amazed at the insights into the mystery of Jesus' Incarnation by these two beloved Catholic writers. Their aproaches are slightly different (Bishop Sheen is slightly more mystical in emphasis and seems to depend on classical catholic spiritual writers, while Sheed guides you in deeply considering the background and implications of the actions and words of our Lord). I've read these again and again and never fail to be enlightened and inspired.