The subject of the Three Kings is open to much debate. Were there actually three? The exact number isn't specified in the Bible. Were they actually kings? More likely they were priests and astrologers. Did they actually give presents of gold, frankincense, and myrrh? If so, why not something more useful?
The details of the Three Wise Men are lively fare for discussion, but ultimately, the important event is the Epiphany itself, the revelation of God in human form to all of mankind.
The Wikipedia has a long and detailed dissection of the subject of the Magi. It's actually very fascinating stuff. (And for those interested, there, too is an entry on the Epiphany. Another good description comes from the New Advent Catholic encyclopedia.)
Then there's the various stories of more recent origin about the Fourth Magi. Henry van Dyke wrote the short story in 1896. It tells of the tardy Wise Man, Artiban, who gets left behind by his more famous brethren. Fiction it may have been, but it's still an inspirational story that tugs at the heartstrings. The story is available from the Gutenberg library.
It was later made into a TV-movie, "The Fourth Wise Man", starring Martin Sheen and Alan Arkin.
Finally, there's the carol We Three Kings, written by John Henry Hopkins, Jr. in 1863. I love the song for its juxtaposition of quiet, almost meditative, melody with a stirring refrain.
We three kings of Orient are
Bearing gifts we traverse afar
Field and fountains, moor and mountains
Following yonder star
Born a King on Bethlehem's plain
Gold I bring to crown Him again
King forever, ceasing never
Over us all to reign
Frankincense to offer have I;
Incense owns a Deity nigh;
Prayer and praising, all men raising,
Worship Him, God most high.
Myrrh is mine, its bitter perfume
Breathes a life of gathering gloom;
Sorrowing, sighing, bleeding, dying,
Sealed in the stone cold tomb.
Glorious now behold Him arise
King and God and Sacrifice
Sounds through the earth and sky
O Star of wonder, star of night
Star with royal beauty bright
Westward leading, still proceeding
Guide us to thy Perfect Light
Happy Three Kings!