I can't say I'm really familiar with the book of Zechariah--in the whole book only a few phrases stood out as vaguely familiar--but it has proven to be a beautiful read. Maybe if Handel’s Messiah would have quoted text from this book, then we would be more acquainted with the prophetic images in it, as we are with many of the Messianic passages in Isaiah.
Nominations for most interesting images: the giant flying scroll, the evil woman in a basket and the two winged women who carry it away, a “unique day, without daytime or nighttime--a day known to the Lord. When evening comes, there will be light.”, and bells on horses labeled “Holy to the Lord”. I can’t say I understand the whole book, but it was refreshing for it's unfamiliarity and forward-pointingness.